JPH04325288A - Optical data recording medium - Google Patents
Optical data recording mediumInfo
- Publication number
- JPH04325288A JPH04325288A JP3095797A JP9579791A JPH04325288A JP H04325288 A JPH04325288 A JP H04325288A JP 3095797 A JP3095797 A JP 3095797A JP 9579791 A JP9579791 A JP 9579791A JP H04325288 A JPH04325288 A JP H04325288A
- Authority
- JP
- Japan
- Prior art keywords
- thin film
- recording
- recording medium
- optical information
- information recording
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 230000003287 optical effect Effects 0.000 title claims abstract description 57
- 239000000758 substrate Substances 0.000 claims abstract description 25
- 230000008859 change Effects 0.000 claims abstract description 12
- -1 Sc2P3 Inorganic materials 0.000 claims abstract description 8
- 229910004369 ThO2 Inorganic materials 0.000 claims abstract description 8
- JYTUFVYWTIKZGR-UHFFFAOYSA-N holmium oxide Inorganic materials [O][Ho]O[Ho][O] JYTUFVYWTIKZGR-UHFFFAOYSA-N 0.000 claims abstract description 8
- ZCUFMDLYAMJYST-UHFFFAOYSA-N thorium dioxide Chemical compound O=[Th]=O ZCUFMDLYAMJYST-UHFFFAOYSA-N 0.000 claims abstract description 8
- FKTOIHSPIPYAPE-UHFFFAOYSA-N samarium(III) oxide Inorganic materials [O-2].[O-2].[O-2].[Sm+3].[Sm+3] FKTOIHSPIPYAPE-UHFFFAOYSA-N 0.000 claims abstract description 7
- MRELNEQAGSRDBK-UHFFFAOYSA-N lanthanum oxide Inorganic materials [O-2].[O-2].[O-2].[La+3].[La+3] MRELNEQAGSRDBK-UHFFFAOYSA-N 0.000 claims abstract description 6
- KTUFCUMIWABKDW-UHFFFAOYSA-N oxo(oxolanthaniooxy)lanthanum Chemical compound O=[La]O[La]=O KTUFCUMIWABKDW-UHFFFAOYSA-N 0.000 claims abstract description 6
- 239000010409 thin film Substances 0.000 claims description 134
- 239000011241 protective layer Substances 0.000 claims description 45
- 239000010410 layer Substances 0.000 claims description 40
- 230000015572 biosynthetic process Effects 0.000 claims description 34
- 229910052714 tellurium Inorganic materials 0.000 claims description 27
- 239000000203 mixture Substances 0.000 claims description 25
- 229910052738 indium Inorganic materials 0.000 claims description 12
- 229910052787 antimony Inorganic materials 0.000 claims description 11
- 229910052732 germanium Inorganic materials 0.000 claims description 11
- PLDDOISOJJCEMH-UHFFFAOYSA-N neodymium oxide Inorganic materials [O-2].[O-2].[O-2].[Nd+3].[Nd+3] PLDDOISOJJCEMH-UHFFFAOYSA-N 0.000 claims description 5
- 229910018047 Sc2O Inorganic materials 0.000 claims description 2
- CMIHHWBVHJVIGI-UHFFFAOYSA-N gadolinium(III) oxide Inorganic materials [O-2].[O-2].[O-2].[Gd+3].[Gd+3] CMIHHWBVHJVIGI-UHFFFAOYSA-N 0.000 abstract description 12
- 239000012528 membrane Substances 0.000 abstract 3
- 229910019714 Nb2O3 Inorganic materials 0.000 abstract 1
- 230000001172 regenerating effect Effects 0.000 abstract 1
- 239000000463 material Substances 0.000 description 42
- 230000006866 deterioration Effects 0.000 description 36
- 238000002425 crystallisation Methods 0.000 description 22
- 230000008025 crystallization Effects 0.000 description 22
- 229910052581 Si3N4 Inorganic materials 0.000 description 10
- 230000000694 effects Effects 0.000 description 10
- 238000002474 experimental method Methods 0.000 description 10
- 239000010931 gold Substances 0.000 description 10
- 229910052711 selenium Inorganic materials 0.000 description 10
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 description 10
- 238000004544 sputter deposition Methods 0.000 description 10
- 229910018110 Se—Te Inorganic materials 0.000 description 7
- 230000035945 sensitivity Effects 0.000 description 7
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 description 6
- 239000000654 additive Substances 0.000 description 6
- 238000005280 amorphization Methods 0.000 description 6
- 239000010408 film Substances 0.000 description 6
- YBMRDBCBODYGJE-UHFFFAOYSA-N germanium dioxide Chemical compound O=[Ge]=O YBMRDBCBODYGJE-UHFFFAOYSA-N 0.000 description 6
- 239000011521 glass Substances 0.000 description 6
- 229910052737 gold Inorganic materials 0.000 description 6
- 238000002844 melting Methods 0.000 description 6
- 230000008018 melting Effects 0.000 description 6
- 230000000996 additive effect Effects 0.000 description 5
- 238000010438 heat treatment Methods 0.000 description 5
- PBCFLUZVCVVTBY-UHFFFAOYSA-N tantalum pentoxide Inorganic materials O=[Ta](=O)O[Ta](=O)=O PBCFLUZVCVVTBY-UHFFFAOYSA-N 0.000 description 5
- 229910005939 Ge—Sn Inorganic materials 0.000 description 4
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 4
- 229910018731 Sn—Au Inorganic materials 0.000 description 4
- 230000031700 light absorption Effects 0.000 description 4
- JKQOBWVOAYFWKG-UHFFFAOYSA-N molybdenum trioxide Chemical compound O=[Mo](=O)=O JKQOBWVOAYFWKG-UHFFFAOYSA-N 0.000 description 4
- 229910052716 thallium Inorganic materials 0.000 description 4
- XOLBLPGZBRYERU-UHFFFAOYSA-N tin dioxide Chemical compound O=[Sn]=O XOLBLPGZBRYERU-UHFFFAOYSA-N 0.000 description 4
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 3
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 3
- 229910052593 corundum Inorganic materials 0.000 description 3
- 230000007423 decrease Effects 0.000 description 3
- 239000003989 dielectric material Substances 0.000 description 3
- FPHIOHCCQGUGKU-UHFFFAOYSA-L difluorolead Chemical compound F[Pb]F FPHIOHCCQGUGKU-UHFFFAOYSA-L 0.000 description 3
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 3
- 230000006872 improvement Effects 0.000 description 3
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 3
- 229910001635 magnesium fluoride Inorganic materials 0.000 description 3
- 238000000034 method Methods 0.000 description 3
- 239000011347 resin Substances 0.000 description 3
- 229920005989 resin Polymers 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- 229910052718 tin Inorganic materials 0.000 description 3
- 229910001845 yogo sapphire Inorganic materials 0.000 description 3
- 229910000831 Steel Inorganic materials 0.000 description 2
- 239000000853 adhesive Substances 0.000 description 2
- 230000001070 adhesive effect Effects 0.000 description 2
- 239000000470 constituent Substances 0.000 description 2
- 239000013078 crystal Substances 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 229910052742 iron Inorganic materials 0.000 description 2
- 230000007246 mechanism Effects 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000012782 phase change material Substances 0.000 description 2
- 230000000704 physical effect Effects 0.000 description 2
- 230000001681 protective effect Effects 0.000 description 2
- HYXGAEYDKFCVMU-UHFFFAOYSA-N scandium(III) oxide Inorganic materials O=[Sc]O[Sc]=O HYXGAEYDKFCVMU-UHFFFAOYSA-N 0.000 description 2
- 229910052814 silicon oxide Inorganic materials 0.000 description 2
- 229910052950 sphalerite Inorganic materials 0.000 description 2
- 239000010959 steel Substances 0.000 description 2
- ZNOKGRXACCSDPY-UHFFFAOYSA-N tungsten(VI) oxide Inorganic materials O=[W](=O)=O ZNOKGRXACCSDPY-UHFFFAOYSA-N 0.000 description 2
- 229910052984 zinc sulfide Inorganic materials 0.000 description 2
- 229910017083 AlN Inorganic materials 0.000 description 1
- 229910015621 MoO Inorganic materials 0.000 description 1
- 229910004205 SiNX Inorganic materials 0.000 description 1
- 229910007709 ZnTe Inorganic materials 0.000 description 1
- 239000012790 adhesive layer Substances 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 150000004770 chalcogenides Chemical class 0.000 description 1
- IVMYJDGYRUAWML-UHFFFAOYSA-N cobalt(II) oxide Inorganic materials [Co]=O IVMYJDGYRUAWML-UHFFFAOYSA-N 0.000 description 1
- 229910052681 coesite Inorganic materials 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 229910052906 cristobalite Inorganic materials 0.000 description 1
- 125000004122 cyclic group Chemical group 0.000 description 1
- 238000005566 electron beam evaporation Methods 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- WPYVAWXEWQSOGY-UHFFFAOYSA-N indium antimonide Chemical compound [Sb]#[In] WPYVAWXEWQSOGY-UHFFFAOYSA-N 0.000 description 1
- 238000007733 ion plating Methods 0.000 description 1
- 230000001678 irradiating effect Effects 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 239000007800 oxidant agent Substances 0.000 description 1
- 229920003229 poly(methyl methacrylate) Polymers 0.000 description 1
- 239000004417 polycarbonate Substances 0.000 description 1
- 229920000515 polycarbonate Polymers 0.000 description 1
- 239000004926 polymethyl methacrylate Substances 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 230000002441 reversible effect Effects 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 235000012239 silicon dioxide Nutrition 0.000 description 1
- LIVNPJMFVYWSIS-UHFFFAOYSA-N silicon monoxide Inorganic materials [Si-]#[O+] LIVNPJMFVYWSIS-UHFFFAOYSA-N 0.000 description 1
- 238000010583 slow cooling Methods 0.000 description 1
- 239000006104 solid solution Substances 0.000 description 1
- 238000004528 spin coating Methods 0.000 description 1
- 229910052682 stishovite Inorganic materials 0.000 description 1
- IATRAKWUXMZMIY-UHFFFAOYSA-N strontium oxide Inorganic materials [O-2].[Sr+2] IATRAKWUXMZMIY-UHFFFAOYSA-N 0.000 description 1
- 230000001629 suppression Effects 0.000 description 1
- OGIDPMRJRNCKJF-UHFFFAOYSA-N titanium oxide Inorganic materials [Ti]=O OGIDPMRJRNCKJF-UHFFFAOYSA-N 0.000 description 1
- 230000009466 transformation Effects 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
- 229910052905 tridymite Inorganic materials 0.000 description 1
- 238000007738 vacuum evaporation Methods 0.000 description 1
Landscapes
- Thermal Transfer Or Thermal Recording In General (AREA)
- Optical Record Carriers And Manufacture Thereof (AREA)
- Optical Recording Or Reproduction (AREA)
Abstract
Description
【０００１】0001
【産業上の利用分野】本発明は、レーザ光線を用いた情
報記録再生装置に用いる光学情報記録媒体、とりわけ書
き換え可能な光学情報記録媒体に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical information recording medium used in an information recording/reproducing apparatus using a laser beam, and more particularly to a rewritable optical information recording medium.
【０００２】0002
【従来の技術】信号を記録，再生、及び消去可能な光学
記録媒体の１例の光ディスクとして、記録薄膜材料にカ
ルコゲン化物を用いた相変化型の光ディスクが知られて
いる。一般には、記録薄膜材料が結晶状態の場合を未記
録状態とし、レーザ照射で急熱急冷して非晶質状態にす
ることで信号を記録する。又、急熱徐冷で再び結晶状態
となり、記録信号は消去される。2. Description of the Related Art A phase change type optical disk using a chalcogenide as a recording thin film material is known as an optical disk that is an example of an optical recording medium on which signals can be recorded, reproduced, and erased. Generally, when the recording thin film material is in a crystalline state, it is considered to be in an unrecorded state, and a signal is recorded by rapidly heating and rapidly cooling it with laser irradiation to make it an amorphous state. Moreover, by rapid heating and slow cooling, it becomes crystalline again, and the recorded signal is erased.
【０００３】記録薄膜材料としては、例えばＴｅ，Ｉｎ
，Ｓｂ，Ｓｅ等を主成分とする非晶質−結晶間で相変化
する材料、或は異なる２種類の結晶構造の間で可逆的に
相変化をおこす物質を用いることが一般的である。As the recording thin film material, for example, Te, In
, Sb, Se, etc., which undergoes a phase change between an amorphous and crystalline structure, or a substance that causes a reversible phase change between two different types of crystal structures is generally used.
【０００４】保護層材料としては、例えば、Ａｌ２Ｏ３
，ＳｉＯ２，ＳｉＯ，Ｔａ２Ｏ５，ＭｏＯ３，ＷＯ３，
ＺｎＳ，ＺｒＯ２，ＡｌＮ，ＢＮ，ＳｉＮｘ，ＴｉＮ，
ＺｒＮ，ＰｂＦ２，ＭｇＦ２等の誘電体或はこれらの適
当な組み合わせが知られている。[0004] As the protective layer material, for example, Al2O3
, SiO2, SiO, Ta2O5, MoO3, WO3,
ZnS, ZrO2, AlN, BN, SiNx, TiN,
Dielectric materials such as ZrN, PbF2, MgF2, or suitable combinations thereof are known.
【０００５】[0005]
【発明が解決しようとする課題】相変化型光ディスクの
記録・消去の繰り返し回数は、記録薄膜や保護層の材料
，ディスク構成，記録・消去ビームパワー等の最適化に
よって向上する。しかし、パーソナルユースとして光デ
ィスクが用いられる場合を考えると、必ずしも良好な環
境の下で使用されるとは限らない。例えば、レーザパワ
ーの変動によって最適パワーからずれた場合においても
、良好な繰り返し特性が得られるような光ディスクであ
ることが望ましい。The number of repetitions of recording and erasing on a phase-change optical disk can be improved by optimizing the materials of the recording thin film and protective layer, the disk configuration, the recording and erasing beam power, and the like. However, when optical discs are used for personal use, they are not necessarily used under favorable environments. For example, it is desirable to have an optical disc that can obtain good repeatability even when the laser power deviates from the optimum power due to fluctuations in laser power.
【０００６】Ｔｅ，Ｉｎ等を主成分とする記録薄膜は、
記録薄膜や保護層の材料によらず、記録パワーが最適値
より高くなると、記録薄膜が変形しやすくなり、繰り返
し回数が制限されてしまう。[0006] A recording thin film mainly composed of Te, In, etc.
Regardless of the material of the recording thin film or the protective layer, when the recording power is higher than the optimum value, the recording thin film becomes easily deformed and the number of repetitions is limited.
【０００７】本発明は、記録・消去の繰り返し特性を向
上、特に記録・消去のためのレーザパワー許容幅を拡大
した光学情報記録媒体を提供することを目的としている
。SUMMARY OF THE INVENTION An object of the present invention is to provide an optical information recording medium that has improved repeatability of recording and erasing, and in particular, has an expanded allowable range of laser power for recording and erasing.
【０００８】[0008]
【課題を解決するための手段】本発明は、上記課題を解
決するために、相変化型光学情報記録媒体の記録薄膜材
料成分に、１０００゜Ｃにおける標準生成自由エネルギ
ーが−９００ｋＪ／ｍｏｌ Ｏ２よりも小さい酸化物を
加えるようにしたものである。[Means for Solving the Problems] In order to solve the above problems, the present invention provides a recording thin film material component of a phase-change optical information recording medium with a standard free energy of formation at 1000°C of -900 kJ/mol O2. Also, small oxides are added.
【０００９】[0009]
【作用】記録薄膜材料成分に１０００゜Ｃにおける標準
生成自由エネルギーが−９００ｋＪ／ｍｏｌ Ｏ２より
も小さい酸化物を加えることにより、最適パワーより高
いパワーで記録する場合でも繰り返しによる記録薄膜の
破壊が生じにくくなる。即ち、良好な繰り返し特性が得
られる記録パワ−の許容範囲が拡大する。[Effect] By adding an oxide whose standard free energy of formation at 1000°C is smaller than -900 kJ/mol O2 to the recording thin film material components, the recording thin film will be destroyed by repetition even when recording is performed at a power higher than the optimum power. It becomes difficult. That is, the permissible range of recording power in which good repetition characteristics can be obtained is expanded.
【００１０】0010
【実施例】以下図面に基づいて本発明を説明する。DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be explained below based on the drawings.
【００１１】本発明の記録媒体の代表的な構造例を図１
に示す。記録，再生、及び消去を行うレーザ光は基板１
の側から入射させる。FIG. 1 shows a typical structural example of the recording medium of the present invention.
Shown below. The laser beam for recording, reproducing, and erasing is on the substrate 1.
Inject it from the side.
【００１２】基板１としては、ＰＭＭＡ，ポリカーボネ
ート等の樹脂或はガラス等、表面の平滑なものを用いる
。光ディスクの場合、通常基板平面８はレーザ光を導く
ためにスパイラル又は同心円状のトラックで覆われてい
る。As the substrate 1, a material with a smooth surface, such as a resin such as PMMA or polycarbonate, or glass, is used. In the case of optical discs, the substrate plane 8 is usually covered with spiral or concentric tracks for guiding the laser light.
【００１３】保護層２，４の材料は、物理的・化学的に
安定、すなわち記録材料の融点よりも、融点及び軟化温
度が高く、かつ記録材料と相固溶しないことが望ましい
。例えば、Ａｌ２Ｏ３，ＳｉＯｘ，Ｔａ２Ｏ５，ＭｏＯ
３，ＷＯ３，ＺｎＳ，ＺｒＯ２，ＡｌＮｘ，ＢＮ，Ｓｉ
Ｎｘ，ＴｉＮ，ＺｒＮ，ＰｂＦ２，ＭｇＦ２等の誘電体
或はこれらの適当な組み合わせからなる。保護層は誘電
体や透明である必要はない。例えば可視光線及び赤外線
に対して光吸収性をもつＺｎＴｅで形成してもよい。又
、保護層２，４を異なる材料で形成すると、熱的及び光
学的なディスク設計の自由度が大きくなる利点がある。
もちろん同一材料で形成してもよい。It is desirable that the materials for the protective layers 2 and 4 are physically and chemically stable, that is, have a melting point and softening temperature higher than the melting point of the recording material, and do not form a solid solution with the recording material. For example, Al2O3, SiOx, Ta2O5, MoO
3, WO3, ZnS, ZrO2, AlNx, BN, Si
It is made of a dielectric material such as Nx, TiN, ZrN, PbF2, MgF2, or a suitable combination thereof. The protective layer need not be dielectric or transparent. For example, it may be formed of ZnTe, which has light absorption properties against visible light and infrared rays. Furthermore, forming the protective layers 2 and 4 from different materials has the advantage of increasing the degree of freedom in thermal and optical disk design. Of course, they may be made of the same material.
【００１４】記録薄膜３は、結晶状態と非晶質状態との
間で可逆的に構造変化をおこす物質、例えばＴｅ又はＩ
ｎ，Ｓｅ等を主成分とする相変化材料からなる。よく知
られた相変化材料の主成分としては、Ｔｅ−Ｓｂ−Ｇｅ
，Ｔｅ−Ｇｅ，Ｔｅ−Ｇｅ−Ｓｎ，Ｔｅ−Ｇｅ−Ｓｎ−
Ａｕ，Ｓｂ−Ｔｅ，Ｓｂ−Ｓｅ−Ｔｅ，Ｉｎ−Ｔｅ，Ｉ
ｎ−Ｓｅ，Ｉｎ−Ｓｅ−Ｔｌ，Ｉｎ−Ｓｂ，Ｉｎ−Ｓｂ
−Ｓｅ，Ｉｎ−Ｓｅ−Ｔｅ等が挙げられる。The recording thin film 3 is made of a substance that reversibly changes its structure between a crystalline state and an amorphous state, such as Te or I.
It is made of a phase change material whose main components are n, Se, etc. The main components of well-known phase change materials include Te-Sb-Ge.
, Te-Ge, Te-Ge-Sn, Te-Ge-Sn-
Au, Sb-Te, Sb-Se-Te, In-Te, I
n-Se, In-Se-Tl, In-Sb, In-Sb
-Se, In-Se-Te and the like.
【００１５】反射層５は、Ａｕ，Ａｌ，Ｎｉ，Ｆｅ，Ｃ
ｒ等の金属元素、或はこれらの合金からなり、記録薄膜
への光吸収効率を高める働きをする。しかし、例えば記
録薄膜３の膜厚を厚くして光吸収効率を高める工夫をす
ることによって、反射層５を設けない構成とすることも
可能である。或は、記録薄膜と保護層を交互に複数回積
み重ねた構成とすることにより、記録薄膜１層あたりの
膜厚が薄くても、全体として光吸収効率を高めることも
できる。The reflective layer 5 is made of Au, Al, Ni, Fe, C.
It is made of metal elements such as r, or alloys thereof, and functions to increase the efficiency of light absorption into the recording thin film. However, it is also possible to create a configuration in which the reflective layer 5 is not provided, for example by increasing the thickness of the recording thin film 3 to increase the light absorption efficiency. Alternatively, by forming a structure in which the recording thin film and the protective layer are alternately stacked a plurality of times, the overall light absorption efficiency can be increased even if the thickness of each recording thin film is thin.
【００１６】保護基板７は、樹脂をスピンコートしたり
、基板と同様の樹脂板、ガラス板、或は金属板等を接着
剤６を用いて貼り合わせることによって形成する。さら
には、２組の記録媒体を中間基板或は反射層を内側にし
て接着剤を用いて貼り合わせることにより、両面から記
録，再生、消去可能な構造としてもよい。The protective substrate 7 is formed by spin coating a resin or by bonding together a resin plate, a glass plate, a metal plate, etc. similar to the substrate using an adhesive 6. Furthermore, by bonding two sets of recording media with an adhesive with the intermediate substrate or reflective layer on the inside, a structure may be created in which recording, reproduction, and erasing can be performed from both sides.
【００１７】記録薄膜，保護層は、通常、電子ビーム蒸
着法，スパタリング法，イオンプレーティング法，ＣＶ
Ｄ法，レーザスパタリング法等によって形成される。The recording thin film and protective layer are usually formed by electron beam evaporation, sputtering, ion plating, CV
It is formed by the D method, laser sputtering method, etc.
【００１８】Ｔｅ或はＩｎを主成分とする種々の書き換
え可能な相変化型光ディスクにおいて、特定の領域に、
同じ信号パターンを繰り返し記録すると、その領域の終
端（一連の信号を書き終えた部分） から記録薄膜が破
れる現象が見られる。以下、この現象を 記録領域終
端部における繰り返し劣化と呼ぶ。記録領域終端部にお
ける繰り返し劣化の現象は、レーザ照射時に、記録薄膜
構成元素がディスク半径方向、或はディスク周方向にわ
ずかに拡散移動し、繰り返しレーザ照射によって、記録
薄膜構成元素の拡散移動量が積算していくことに起因す
ると考えている。記録領域終端部における繰り返し劣化
は、特に、記録パワーが高い時に顕著である。この現象
を解決する手段として、記録薄膜材料成分に酸化物を添
加することを試みた。その結果、１０００゜Ｃにおける
標準生成自由エネルギーが−９００ｋＪ／ｍｏｌ Ｏ２
よりも小さい酸化物を添加した場合に、記録領域終端部
における繰り返し劣化が軽減した。特に、記録パワーが
最適値よりも若干高いときに繰り返し劣化の軽減が顕著
であった。酸化物を記録薄膜中に導入する方法としては
、１）記録薄膜の主成分と、記録薄膜中に添加したい酸
化物の混合ターゲットを作成してスパタリング法等によ
り記録薄膜を成膜する。２）記録薄膜の主成分と、添加
する酸化物、それぞれ独立のターゲットを作成してスパ
タリング法、或は真空蒸着法等によって記録薄膜を成膜
する、等の方法が考えられる。[0018] In various rewritable phase change optical discs containing Te or In as a main component, in a specific area,
When the same signal pattern is repeatedly recorded, there is a phenomenon in which the recording thin film breaks from the end of the area (the part where a series of signals has been written). Hereinafter, this phenomenon will be referred to as repeated deterioration at the end of the recording area. The phenomenon of repeated deterioration at the end of the recording area is caused by the fact that during laser irradiation, the elements constituting the recording thin film slightly diffuse and move in the radial direction of the disk or in the circumferential direction of the disk. I think this is due to the fact that it accumulates. The repeated deterioration at the end of the recording area is particularly noticeable when the recording power is high. As a means to solve this phenomenon, an attempt was made to add oxides to the recording thin film material components. As a result, the standard free energy of formation at 1000°C is -900 kJ/mol O2
When a smaller oxide was added, repeated deterioration at the end of the recording area was reduced. Particularly, when the recording power was slightly higher than the optimum value, the reduction in repeated deterioration was remarkable. The method for introducing an oxide into a recording thin film is as follows: 1) A mixed target of the main component of the recording thin film and the oxide desired to be added to the recording thin film is prepared, and the recording thin film is formed by sputtering or the like. 2) A possible method is to prepare separate targets for the main component of the recording thin film and the oxide to be added, and then deposit the recording thin film by sputtering, vacuum evaporation, or the like.
【００１９】Ｔｅ或はＩｎを主成分とし、記録・消去の
繰り返し可能な相変化型記録薄膜組成は無限の組合せが
あり、その全てに対して酸化物の添加効果を実験的に確
認することは不可能である。しかし、すでに公知になっ
ている、Ｔｅ或はＩｎを主成分とし記録・消去の繰り返
し可能な代表的相変化型記録薄膜の主成分は、Ｔｅ−Ｓ
ｂ，Ｔｅ−Ｇｅ，Ｔｅ−Ｓｅ，Ｉｎ−Ｔｅ，Ｉｎ−Ｓｂ
，Ｉｎ−Ｓｅと大きく分類することができる。上記分類
で代表的な記録薄膜組成について種々の酸化物の添加効
果を調べたところ、１０００゜Ｃにおける標準生成自由
エネルギーが−９００ｋＪ／ｍｏｌ Ｏ２よりも小さい
酸化物を、適当量記録薄材料成分として添加した場合に
のみ、記録・消去の繰り返し劣化の抑制効果が顕著であ
った。実験結果から、前記物性を有する酸化物の添加が
、Ｔｅ或はＩｎを主成分とし、記録・消去の繰り返し可
能な相変化型記録薄膜の記録・消去の繰り返し劣化、よ
り具体的には記録領域終端部の繰り返し劣化の抑制に効
果があると判断できる。There are infinite combinations of phase-change recording thin film compositions that are mainly composed of Te or In and can be repeatedly used for recording and erasing, and it is difficult to experimentally confirm the effect of adding oxides to all of them. It's impossible. However, the main component of a typical phase-change recording thin film that is already publicly known and is mainly composed of Te or In and can be repeatedly recorded and erased is Te-S.
b, Te-Ge, Te-Se, In-Te, In-Sb
, In-Se. When we investigated the effects of adding various oxides to typical recording thin film compositions in the above classification, we found that when an appropriate amount of an oxide with a standard free energy of formation at 1000°C smaller than -900 kJ/mol O2 was used as a recording thin material component. Only when it was added, the effect of suppressing deterioration due to repeated recording and erasing was remarkable. From the experimental results, it has been found that the addition of oxides having the above-mentioned physical properties causes deterioration of a phase-change recording thin film that is mainly composed of Te or In and can be repeatedly recorded and erased, more specifically, the recording area. It can be judged that this is effective in suppressing repeated deterioration of the terminal end.
【００２０】前述のように、通常、消去の可能な相変化
形光ディスク装置の場合には、記録薄膜の非晶質相を記
録信号に対応させ、結晶相を消去状態に対応させる。
又、光学的に識別しうる２つの異なる結晶状態をそれぞ
れ記録、消去に対応させる場合もある。いずれの場合で
も、光学的に識別しうる２つの記録薄膜の状態のうち、
少なくともいずれかの状態を得るには、レーザ光線の照
射によって、記録薄膜を溶融させる、或は相変態の転移
温度以上に昇温させる必要がある。溶融している状態、
或は高温状態の記録薄膜では、記録薄膜の構成元素が拡
散移動しやすい。すなわち、記録・消去の繰り返し可能
な相変化型光ディスクでは、その記録・消去メカニズム
上、記録薄膜が繰り返し劣化する可能性を内在している
と言える。融点が高く、熱的に安定な酸化物を記録薄膜
材料として添加した場合に繰り返し劣化が抑制されるメ
カニズムはよくわからないが、添加物が他の記録薄膜構
成元素と固溶せず、レーザ照射時の記録薄膜主成分の結
晶化現象になんらかの影響を与えていることが考えられ
る。As described above, in the case of an erasable phase-change optical disk device, the amorphous phase of the recording thin film corresponds to the recording signal, and the crystalline phase corresponds to the erased state. Furthermore, there are cases where two different crystal states that can be optically distinguished correspond to recording and erasing, respectively. In either case, of the two optically distinguishable states of the recording thin film,
In order to obtain at least one of these states, it is necessary to melt the recording thin film or to raise the temperature to a temperature equal to or higher than the phase transformation transition temperature by irradiating the recording thin film with a laser beam. molten state,
Alternatively, in a recording thin film in a high temperature state, constituent elements of the recording thin film are likely to diffuse and move. In other words, it can be said that in a phase-change optical disk that allows repeated recording and erasing, there is an inherent possibility that the recording thin film will deteriorate repeatedly due to its recording and erasing mechanism. The mechanism by which repeated deterioration is suppressed when a thermally stable oxide with a high melting point is added as a recording thin film material is not well understood; This is thought to have some influence on the crystallization phenomenon of the main component of the recording thin film.
【００２１】さらに検討を重ねた結果、記録薄膜に接し
て不活性層を設けた構造において、この不活性層の主成
分を１０００゜Ｃにおける標準生成自由エネルギーが−
９００ｋＪ／ｍｏｌ Ｏ２よりも小さい酸化物とすると
、記録薄膜材料成分として酸化物を添加した場合と同様
に、繰り返し劣化が抑制されることが確認された。この
ことは、レーザ照射部において不活性層の存在により記
録薄膜の結晶化現象になんらかの変化が生じていること
をうかがわせる。As a result of further studies, in a structure in which an inactive layer is provided in contact with the recording thin film, the standard free energy of formation of the main component of this inactive layer at 1000°C is -
It was confirmed that when the oxide was smaller than 900 kJ/mol O2, repeated deterioration was suppressed as in the case where the oxide was added as a component of the recording thin film material. This suggests that some change occurs in the crystallization phenomenon of the recording thin film due to the presence of the inactive layer in the laser irradiated area.
【００２２】以下に 具体的な例をもって本発明を詳
述する。
実施例１
代表的な記録薄膜組成として、Ｇｅ２Ｓｂ２Ｔｅ５を選
び、種々の酸化物を添加した場合の、記録・消去の繰り
返し特性、特に繰り返しに対する記録パワーの許容範囲
を比較した。Ｇｅ２Ｓｂ２Ｔｅ５は、良好な記録・消去
特性、及び繰り返し特性が得られる材料として知られて
いる（特開昭６２−２０９７４２号広報）。The present invention will be explained in detail below using specific examples. Example 1 Ge2Sb2Te5 was selected as a typical recording thin film composition, and when various oxides were added, the repeatability of recording and erasing, especially the allowable range of recording power for repetition, was compared. Ge2Sb2Te5 is known as a material that provides good recording/erasing characteristics and repeatability (Japanese Patent Laid-Open No. 209742/1983).
【００２３】図１にディスク構造を示す。基板の材質は
５．２５インチ径のガラスとした。記録薄膜の膜厚は６
０ｎｍで、窒化ケイ素（Ｓｉ３Ｎ４）からなる保護層が
、その両側をサンドイッチしている。保護層の膜厚は、
光学的に最適な特性が得られるように決定した。具体的
には基板側の膜厚が１５０ｎｍ、記録薄膜上には２００
ｎｍ設けた。
反射層材料には金（Ａｕ）を用い、膜厚は２０ｎｍとし
た。各層の形成はスパタリング法により行った。記録薄
膜の成膜は、主成分Ｇｅ２Ｓｂ２Ｔｅ５ターゲットと添
加材となる酸化物ターゲットを用意し、共スパタリング
法によって、記録薄膜構成材料に占める酸化物の割合が
５ｗｔ％となるようにした。FIG. 1 shows the disk structure. The material of the substrate was glass with a diameter of 5.25 inches. The thickness of the recording thin film is 6
A protective layer of silicon nitride (Si3N4) of 0 nm is sandwiched on both sides. The thickness of the protective layer is
It was determined to obtain the optimum optical characteristics. Specifically, the film thickness on the substrate side is 150 nm, and the film thickness on the recording thin film is 200 nm.
nm was provided. Gold (Au) was used as the reflective layer material, and the film thickness was 20 nm. Each layer was formed by a sputtering method. The recording thin film was formed by preparing a main component Ge2Sb2Te5 target and an oxide target serving as an additive, and using a co-sputtering method so that the proportion of oxide in the recording thin film constituent material was 5 wt%.
【００２４】上記構成のディスクを用いて記録・消去の
繰り返し試験を行った。ここで、レーザビーム（波長：
８３０ｎｍ）とディスクの相対速度は１０ｍ／ｓｅｃと
し、記録・消去の周波数５ＭＨｚで信号を１万回重ね書
き（オーバーライト記録）した。（以下の実施例におい
て記録・消去特性を調べる場合の記録条件は、本条件を
踏襲している。）この時、Ｃ／Ｎが５０ｄＢ以上、消去
率が２５ｄＢ以上、かつ記録領域終端部における劣化長
さ（記録マークの再生信号の振幅が小さくなっている領
域の長さ）が０．０１ｍｍ以下となる記録・消去パワー
範囲を調べた。Ｃ／Ｎが５０ｄＢ以上、消去率が２５ｄ
Ｂ以上という値はディジタル記録として十分に実用的な
値である。このような記録・消去条件を満たすパワー範
囲を以下、最適パワー範囲と呼ぶことにする。記録パワ
ーの最適パワー範囲を（表１）に示す。（表１）には、
添加した酸化物の融点、及び１０００゜Ｃにおける標準
生成自由エネルギーを併記した。各物性値は、化学便覧
改訂３版基礎編，及び鉄鋼便覧第３版（日本鉄鋼協会編
）から引用した。A repeated recording/erasing test was conducted using the disk constructed as described above. Here, the laser beam (wavelength:
830 nm) and the disk was set to 10 m/sec, and signals were overwritten 10,000 times (overwrite recording) at a recording/erasing frequency of 5 MHz. (The recording conditions when examining the recording/erasing characteristics in the following examples follow these conditions.) At this time, the C/N is 50 dB or more, the erasure rate is 25 dB or more, and there is deterioration at the end of the recording area. The recording/erasing power range in which the length (the length of the region where the amplitude of the reproduced signal of the recording mark is small) is 0.01 mm or less was investigated. C/N is 50dB or more, erasure rate is 25d
A value of B or more is a sufficiently practical value for digital recording. The power range that satisfies such recording/erasing conditions will hereinafter be referred to as the optimal power range. The optimum power range of recording power is shown in (Table 1). (Table 1) includes
The melting point of the added oxide and the standard free energy of formation at 1000°C are also listed. Each physical property value was quoted from the Chemical Handbook Revised 3rd Edition Basic Edition and the Steel Handbook 3rd Edition (edited by the Japan Iron and Steel Institute).
【００２５】[0025]
【表１】[Table 1]
【００２６】（表１）より、１０００゜Ｃにおける標準
生成自由エネルギーが−９００ｋＪ／ｍｏｌＯ２よりも
小さい酸化物を添加した場合に、良好な繰り返し記録・
消去が行える記録パワー範囲が拡大することがわかる。
このような繰り返し特性の向上は、酸化物を添加するこ
とによって記録領域終端部における繰り返し劣化が抑制
されることに起因していることが光学顕微鏡観察によっ
て確認された。一方、１０００゜Ｃにおける標準生成自
由エネルギーが−９００ｋＪ／ｍｏｌ Ｏ２よりも大き
い酸化物の例として取りあげたＣｏＯ，ＧｅＯ２，Ｓｎ
Ｏ２，Ｔａ２Ｏ５，ＴｉＯ，Ｖ２Ｏ３，ＷＯ２，ＺｎＯ
を添加した記録薄膜を有するディスクは、いずれも良好
な繰り返し特性が得られていないことがわかる。これら
の結果から、繰り返し特性の向上を目的として記録薄膜
に添加するのに好ましい材料は、熱的に安定、すなわち
目安として、１０００゜Ｃにおける標準生成自由エネル
ギーが−９００ｋＪ／ｍｏｌ Ｏ２よりも小さい酸化物
であると、結論できる。From (Table 1), when adding an oxide whose standard free energy of formation at 1000°C is less than -900 kJ/molO2, good repeatability recording and
It can be seen that the recording power range in which erasing can be performed is expanded. It was confirmed by optical microscopic observation that such improvement in the repeatability is due to the suppression of repeatability deterioration at the end of the recording area by adding the oxide. On the other hand, CoO, GeO2, and Sn, which are taken as examples of oxides whose standard free energy of formation at 1000°C is greater than -900 kJ/mol O2,
O2, Ta2O5, TiO, V2O3, WO2, ZnO
It can be seen that none of the disks having a recording thin film containing . From these results, the preferred materials to be added to the recording thin film for the purpose of improving repeatability are those that are thermally stable, that is, as a guideline, oxidized materials with a standard free energy of formation of less than -900 kJ/mol O2 at 1000°C. We can conclude that it is a thing.
【００２７】さらに、記録薄膜に添加する酸化物の適量
を実験によりもとめた。図２に一例として、Ｇｅ２Ｓｂ
２Ｔｅ５−Ｇｄ２Ｏ３記録薄膜を有するディスクの、記
録薄膜に占めるＧｄ２Ｏ３の重量比と消去率の関係を示
す。前もって、１８ｍＷの記録パワーで信号を記録し、
しかる後に直流的にレーザ光を照射して消去（結晶化）
を行った。Ｇｄ２Ｏ３量が少ない場合には、信号記録用
と同一のレーザスポットを用いて結晶化（消去）が行え
る。すなわち、いわゆる単一ビームによる重ね書きが可
能である。Ｇｄ２Ｏ３添加量を変えた場合の消去特性で
は、Ｇｄ２Ｏ３量が８ｗｔ％以下の場合には２５ｄＢ以
上の消去率が得られるが、それ以上の添加では消去率が
低下することが図２よりわかる。これは、Ｇｄ２Ｏ３量
が多くなると、記録薄膜の結晶化速度、或は結晶化感度
が低下することによる。Ｈｏ２Ｏ３，Ｌａ２Ｏ３，Ｎｄ
２Ｏ３，Ｓｃ２Ｏ３，Ｓｍ２Ｏ３，ＳｒＯ，Ｔｂ２Ｏ３
，ＴｈＯ２，Ｙ２Ｏ３に関してもＧｄ２Ｏ３添加と同様
の実験を行った結果、いずれの酸化物の場合でも、記録
薄膜に占める重量比が１０ｗｔ％以上では、消去率の低
下が著しくなり、記録・消去可能な光ディスクの記録薄
膜として好ましくないことがわかった。Furthermore, the appropriate amount of oxide to be added to the recording thin film was determined through experiments. As an example in FIG. 2, Ge2Sb
3 shows the relationship between the weight ratio of Gd2O3 in the recording thin film and the erasure rate of a disk having a 2Te5-Gd2O3 recording thin film. In advance, the signal was recorded with a recording power of 18 mW,
After that, it is erased (crystallized) by direct current laser beam irradiation.
I did it. When the amount of Gd2O3 is small, crystallization (erasing) can be performed using the same laser spot as for signal recording. That is, overwriting by a so-called single beam is possible. Regarding the erasing characteristics when the amount of Gd2O3 added is changed, it can be seen from FIG. 2 that when the amount of Gd2O3 is 8 wt% or less, an erasing rate of 25 dB or more is obtained, but when it is added more than that, the erasing rate decreases. This is because as the amount of Gd2O3 increases, the crystallization speed or crystallization sensitivity of the recording thin film decreases. Ho2O3, La2O3, Nd
2O3, Sc2O3, Sm2O3, SrO, Tb2O3
, ThO2, and Y2O3 as well as the Gd2O3 addition. As a result, in the case of any oxide, when the weight ratio in the recording thin film is 10 wt% or more, the erasing rate decreases significantly, and recording and erasing is not possible. It was found that this is not preferable as a recording thin film for optical discs.
【００２８】又、上記特性を有する酸化物を複数種組み
合わせて適当量記録薄膜に添加した場合にも、顕著な繰
り返し特性の向上が見られた。（表１）に一例として、
Ｇｄ２Ｏ３とＨｏ２Ｏ３をそれぞれ記録薄膜材料の２．
５ｗｔ％相当を添加した場合の繰り返し特性の向上を示
した。複数種の酸化物を添加する場合においても、添加
酸化物の総量が記録薄膜に対して１０ｗｔ％を越えない
ようにしなければならないことが種々の実験より間接的
に確認された。Also, when a suitable amount of a combination of a plurality of oxides having the above characteristics was added to the recording thin film, a remarkable improvement in the repeatability was observed. As an example (Table 1),
Gd2O3 and Ho2O3 were used as recording thin film materials in 2.
It was shown that the repeatability was improved when the amount equivalent to 5 wt% was added. It has been indirectly confirmed through various experiments that even when multiple types of oxides are added, the total amount of the added oxides must not exceed 10 wt % based on the recording thin film.
【００２９】実施例２
主成分の組成が（Ｇｅ）ｘ（Ｓｂ）ｙ（Ｔｅ）ｚ，ｘ＋
ｙ＋ｚ＝１ で、さらに１０００゜Ｃにおける標準生
成自由エネルギーが−９００ｋＪ／ｍｏｌ Ｏ２よりも
小さい酸化物（具体的にはＧｄ２Ｏ３，Ｈｏ２Ｏ３，Ｌ
ａ２Ｏ３，Ｎｄ２Ｏ３，Ｓｃ２Ｏ３，Ｓｍ２Ｏ３，Ｓｒ
Ｏ，Ｔｂ２Ｏ３，ＴｈＯ２，Ｙ２Ｏ３の１０種類の酸化
物を選んで実験）を添加した記録薄膜を有するディスク
をスパタリング法を用いて種々作成し、結晶化特性，非
晶質化特性，及び１万回の記録・消去の繰り返し特性を
調べた。ディスク構造を図１に示す。記録薄膜の膜厚は
６０ｎｍで、窒化ケイ素からなる保護層がその両側をサ
ンドイッチしている。保護層の膜厚は、基板側が１５０
ｎｍ，反射層側が２００ｎｍとした。反射層は膜厚２０
ｎｍのＡｕ薄膜で形成した。Example 2 The composition of the main component is (Ge)x(Sb)y(Te)z,x+
y+z=1, and the standard free energy of formation at 1000°C is smaller than -900 kJ/mol O2 (specifically, Gd2O3, Ho2O3, L
a2O3, Nd2O3, Sc2O3, Sm2O3, Sr
Various types of disks with recording thin films doped with O, Tb2O3, ThO2, and Y2O3 (O, Tb2O3, ThO2, and Y2O3) were prepared using the sputtering method, and the crystallization characteristics, amorphization characteristics, and 10,000 times We investigated the repeated recording and erasing characteristics of . The disk structure is shown in Figure 1. The thickness of the recording thin film was 60 nm, and a protective layer made of silicon nitride sandwiched it on both sides. The thickness of the protective layer is 150 mm on the substrate side.
nm, and the reflective layer side was 200 nm. The thickness of the reflective layer is 20
It was formed from a nm thin Au film.
【００３０】実験の結果、結晶化・非晶質化感度がとも
に良好（単一ビームによる重ね書きを考慮して、結晶化
に必要な加熱時間が１００ｎｓｅｃ以下）で、かつ記録
・消去の繰り返し時に記録領域終端部劣化が生じにくい
Ｇｅ−Ｓｂ−Ｔｅ主成分の組成範囲は、
（Ｇｅ）ｘ（Ｓｂ）ｙ（Ｔｅ）ｚ
０．１０≦ｘ≦０．３５ ０．１０≦ｙ０．４５
≦ｚ≦０．６５ ｘ＋ｙ＋ｚ＝１で、添加する酸
化物の適量は多くても１０ｗｔ％であった。実施例１で
示したのと同様に、これら酸化物の添加により、良好な
繰り返し記録・消去が行えるパワー範囲が拡大すること
が確認された。添加物としては、１０００゜Ｃにおける
標準生成自由エネルギーが−９００ｋＪ／ｍｏｌ Ｏ２
よりも小さい酸化物を複数種組み合わせてもよい。As a result of experiments, it was found that both crystallization and amorphization sensitivity were good (heating time required for crystallization was 100 nsec or less, taking into account overwriting by a single beam), and that the sensitivity was good during repeated recording and erasing. The composition range of the Ge-Sb-Te main component in which deterioration at the end of the recording area is less likely to occur is: (Ge)x(Sb)y(Te)z 0.10≦x≦0.35 0.10≦y0.45
≦z≦0.65 x+y+z=1, and the appropriate amount of the oxide to be added was at most 10 wt%. As shown in Example 1, it was confirmed that the addition of these oxides expanded the power range in which good repeated recording and erasing could be performed. As an additive, the standard free energy of formation at 1000°C is -900 kJ/mol O2
You may combine multiple types of oxides smaller than .
【００３１】記録薄膜主成分のＧｅ−Ｓｂ−Ｔｅ組成範
囲は、図３のＡ，Ｂ，Ｃ，Ｄ，Ｅで囲まれた範囲である
。The composition range of Ge--Sb--Te, which is the main component of the recording thin film, is the range surrounded by A, B, C, D, and E in FIG.
【００３２】比較のために、１０００゜Ｃにおける標準
生成自由エネルギーが−９００ｋＪ／ｍｏｌＯ２よりも
大きい酸化物を添加した記録薄膜を有するディスクを作
成して、繰り返し特性を調べた。実施例で用いた、Ｃｏ
Ｏ，ＧｅＯ２，ＳｎＯ２，Ｔａ２Ｏ５，ＴｉＯ，Ｖ２Ｏ
３，ＷＯ２，ＺｎＯの８種類の酸化物について実験を行
った結果、いずれの酸化物を用いた場合にも、繰り返し
特性の向上は見られない、或は極わずかであった。For comparison, a disk having a recording thin film doped with an oxide whose standard free energy of formation at 1000° C. is greater than -900 kJ/molO2 was prepared and its cyclic characteristics were investigated. Co used in the examples
O, GeO2, SnO2, Ta2O5, TiO, V2O
As a result of experiments conducted on eight types of oxides, ie, No. 3, WO2, and ZnO, no improvement in repeatability was observed, or was very slight, no matter which oxide was used.
【００３３】記録薄膜主成分のＧｅ−Ｓｂ−Ｔｅ組成範
囲をさらに詳しく検討した結果、
（Ｇｅ）ｘ（Ｓｂ）ｙ（Ｔｅ）ｚ
０．１０≦ｘ≦０．３５ ０．１０≦ｙ０．４５
≦ｚ≦０．６５ ｘ＋ｙ＋ｚ＝１の組成範囲の中
でも、
（Ｇｅ２Ｓｂ２Ｔｅ５）ｘ（ＧｅＳｂ２Ｔｅ４）１−ｘ
０≦ｘ≦１
で表わされる範囲の記録薄膜組は、とりわけ結晶化速度
が速い（特開昭６２−２０９７４２号公報）と同時に、
繰り返しに記録・消去に伴う記録領域終端部の劣化が顕
著であった。結晶化速度が速いことは重ね書き可能な相
変化型光ディスクにとって非常に好ましいことである。
それ故、記録薄膜に熱的に安定な酸化物を添加すること
による繰り返し劣化の抑制効果は、
（Ｇｅ２Ｓｂ２Ｔｅ５）ｘ（ＧｅＳｂ２Ｔｅ４）１−ｘ
０≦ｘ≦１
組成において顕著、かつ重要である。As a result of a more detailed study of the Ge-Sb-Te composition range of the main component of the recording thin film, (Ge)x(Sb)y(Te)z 0.10≦x≦0.35 0.10≦y0.45
≦z≦0.65 Within the composition range of x+y+z=1, (Ge2Sb2Te5)x(GeSb2Te4)1-x
The recording thin film set in the range expressed by 0≦x≦1 has a particularly fast crystallization speed (Japanese Unexamined Patent Publication No. 62-209742), and at the same time
Deterioration at the end of the recording area due to repeated recording and erasing was remarkable. A high crystallization rate is highly desirable for a rewritable phase change optical disc. Therefore, the effect of suppressing repeated deterioration by adding a thermally stable oxide to the recording thin film is (Ge2Sb2Te5)x(GeSb2Te4)1-x
0≦x≦1 Significant and important in composition.
【００３４】実施例３
実施例１，２では、記録薄膜をＧｅ−Ｓｂ−Ｔｅに熱的
に安定な酸化物を加えた組成とすることによって、記録
・消去の繰り返し時の記録領域終端部劣化が生じにくく
なることを示した。他にもＴｅ或はＩｎを主成分とする
記録薄膜、例えばＴｅ−Ｇｅ，Ｔｅ−Ｇｅ−Ｓｎ，Ｔｅ
−Ｇｅ−Ｓｎ−Ａｕ，Ｓｂ−Ｔｅ，Ｓｂ−Ｓｅ−Ｔｅ，
Ｉｎ−Ｔｅ，Ｉｎ−Ｓｅ，Ｉｎ−Ｓｅ−Ｔｌ，Ｉｎ−Ｓ
ｂ，Ｉｎ−Ｓｂ−Ｓｅ，Ｉｎ−Ｓｅ−Ｔｅに熱的に安定
な酸化物（具体的には、１０００゜Ｃにおける標準生成
自由エネルギーが−９００ｋＪ／ｍｏｌ Ｏ２よりも小
さい酸化物）を加えることにより、いずれも記録・消去
繰り返し時の記録領域終端部劣化が生じにくくなった。
一例として、（表２）に主成分が（ＩｎＳｂ）２Ｔｅで
種々の酸化物を添加した記録薄膜を有する光ディスクの
繰り返し特性を示す。ディスクの構造は、ガラス基板、
記録薄膜の膜厚は４０ｎｍで、窒化ケイ素からなる保護
層がその両側をサンドイッチしている。保護層の膜厚を
、基板側を１５０ｎｍ，反射層側が２００ｎｍとした。
実施例１に示した記録条件で、重ね書きで信号を１００
０回記録した場合に、記録領域終端部の劣化が０．０３
ｍｍ以下となるパワー領域（最適記録パワー範囲）を（
表２）に示してある。Example 3 In Examples 1 and 2, the recording thin film was made of a composition of Ge-Sb-Te with a thermally stable oxide added, thereby reducing the deterioration at the end of the recording area during repeated recording and erasing. It was shown that this is less likely to occur. In addition, recording thin films mainly composed of Te or In, such as Te-Ge, Te-Ge-Sn, Te
-Ge-Sn-Au, Sb-Te, Sb-Se-Te,
In-Te, In-Se, In-Se-Tl, In-S
Adding a thermally stable oxide (specifically, an oxide whose standard free energy of formation at 1000°C is smaller than -900 kJ/mol O2) to b, In-Sb-Se, In-Se-Te. As a result, deterioration at the end of the recording area during repeated recording and erasing is less likely to occur. As an example, Table 2 shows the repetition characteristics of an optical disk having a recording thin film whose main component is (InSb)2Te and various oxides added thereto. The structure of the disk is a glass substrate,
The thickness of the recording thin film was 40 nm, and a protective layer made of silicon nitride sandwiched it on both sides. The thickness of the protective layer was 150 nm on the substrate side and 200 nm on the reflective layer side. Under the recording conditions shown in Example 1, the signal was overwritten by 100
When recording 0 times, the deterioration at the end of the recording area is 0.03
The power range (optimum recording power range) below mm is (
Table 2).
【００３５】[0035]
【表２】[Table 2]
【００３６】（表２）より、１０００゜Ｃにおける標準
生成自由エネルギーが−９００ｋＪ／ｍＯ２よりも小さ
い酸化物を添加した場合に、良好な繰り返し記録・消去
が行える記録パワー範囲が拡大することがわかる。一方
、１０００゜Ｃにおける標準生成自由エネルギーが−９
００ｋＪ／ｍｏｌ Ｏ２よりも大きい酸化物の例として
取りあげたＣｏＯ，ＧｅＯ２，ＳｎＯ２，Ｔａ２Ｏ５，
ＴｉＯ，Ｖ２Ｏ３，ＷＯ２，ＺｎＯを添加した記録薄膜
を有するディスクは、いずれも良好な繰り返し特性が得
られていないことがわかる。これらの結果から、繰り返
し特性の向上を目的として記録薄膜に添加するのに好ま
しい材料は、熱的に安定、すなわち目安として、１００
０゜Ｃにおける標準生成自由エネルギーが−９００ｋＪ
／ｍｏｌ Ｏ２よりも小さい酸化物であると、結論でき
る。[0036] From Table 2, it can be seen that when an oxide whose standard free energy of formation at 1000°C is smaller than -900 kJ/mO2 is added, the recording power range in which good repeated recording and erasing can be performed is expanded. . On the other hand, the standard free energy of formation at 1000°C is -9
CoO, GeO2, SnO2, Ta2O5, taken as examples of oxides larger than 00kJ/mol O2,
It can be seen that none of the disks having recording thin films containing TiO, V2O3, WO2, and ZnO have good repeatability. From these results, it is clear that materials preferable to be added to the recording thin film for the purpose of improving repeatability are thermally stable, that is, as a guide, 100%
Standard free energy of formation at 0°C is -900kJ
It can be concluded that the oxide is smaller than /mol O2.
【００３７】又、結晶化速度が比較的遅く、１ビームに
よる重ね書きができない、或は困難な材料からなる記録
薄膜に対しても、記録薄膜への熱的に安定な酸化物の添
加効果が認められた。例えば、Ｔｅ−Ｇｅ−Ｓｎ−Ａｕ
記録薄膜を有する光ディスクは、記録薄膜の結晶化速度
が比較的遅く、１ビームによる重ね書きは困難であるが
、記録・再生用と、消去用の２つのレーザ光を用い、消
去用のレーザスポットを記録用のレーザスポットよりも
相対的に長くすることで、記録・消去の繰り返しを行う
ことができる（特願昭６０−１１２４２０号公報）。Ｔ
ｅ−Ｇｅ−Ｓｎ−Ａｕ記録薄膜の場合でも、１種類、或
は複数種の１０００゜Ｃにおける標準生成自由エネルギ
ーが−９００ｋＪ／ｍｏｌ Ｏ２よりも小さい酸化物を
記録薄膜に添加することによって、記録領域終端部の繰
り返し劣化が抑制されることが確かめられた。Furthermore, even for recording thin films made of materials whose crystallization speed is relatively slow and overwriting with one beam is difficult or impossible, the effect of adding a thermally stable oxide to the recording thin film is Admitted. For example, Te-Ge-Sn-Au
Optical discs with a recording thin film have a relatively slow crystallization speed, making overwriting with one beam difficult. By making the laser spot relatively longer than the recording laser spot, recording and erasing can be repeated (Japanese Patent Application No. 112420/1982). T
Even in the case of an e-Ge-Sn-Au recording thin film, recording can be achieved by adding one or more kinds of oxides whose standard free energy of formation at 1000°C is smaller than -900 kJ/mol O2 to the recording thin film. It was confirmed that repeated deterioration at the end of the region was suppressed.
【００３８】実施例４
実施例１では、Ｇｅ２Ｓｂ２Ｔｅ５記録薄膜に熱的に安
定な酸化物、すなわち１種類、或は複数種の１０００゜
Ｃにおける標準生成自由エネルギーが−９００ｋＪ／ｍ
ｏｌＯ２よりも小さい酸化物を添加することによって、
記録・消去の繰り返し特性が向上することを示した。次
に、記録薄膜中に酸化物を加えず、代わりに記録薄膜に
接して記録薄膜の両側、或は片側に熱的に安定な酸化物
を設けることによって、繰り返しにおける記録領域終端
部劣化が抑制されるかを調べた。Example 4 In Example 1, the Ge2Sb2Te5 recording thin film was made of a thermally stable oxide, that is, one or more types of oxide, whose standard free energy of formation at 1000°C was -900 kJ/m.
By adding an oxide smaller than olO2,
It was shown that the repeatability of recording and erasing was improved. Next, by not adding oxide to the recording thin film and instead providing a thermally stable oxide on both sides or one side of the recording thin film in contact with the recording thin film, deterioration at the end of the recording area due to repetition is suppressed. I investigated whether it would be possible.
【００３９】（表３）にＧｅ２Ｓｂ２Ｔｅ５記録薄膜の
両側に酸化物で形成した不活性層を設けた光ディスクの
繰り返し特性を示す。この時のディスクの構造を図４に
示す。
基板の材質は５．２５インチ径のガラスとした。記録薄
膜の膜厚は６０ｎｍで、膜厚５ｎｍの不活性層がその両
側をサンドイッチしている。さらにその両側を窒化ケイ
素（Ｓｉ３Ｎ４）からなる保護層がサンドイッチしてい
る。保護層の膜厚は、基板側を１５０ｎｍ、反射層側を
２００ｎｍとした。反射層材料には金（Ａｕ）を用い、
膜厚は２０ｎｍとした。各層の形成はスパタリング法に
より行った。実施例１に示した記録条件で、重ね書きで
信号を１万回記録した場合に、記録領域終端部の劣化が
０．０１ｍｍ以下となるパワー領域（最適記録パワー範
囲）を（表３）に示してある。（表４）には、不活性層
材料に選んだ酸化物の融点、及び１０００゜Ｃにおける
標準生成自由エネルギーを併記した。Table 3 shows the repetition characteristics of an optical disk in which an inactive layer made of an oxide is provided on both sides of a Ge2Sb2Te5 recording thin film. The structure of the disk at this time is shown in FIG. The material of the substrate was glass with a diameter of 5.25 inches. The recording thin film had a thickness of 60 nm, and was sandwiched on both sides by an inactive layer with a thickness of 5 nm. Furthermore, a protective layer made of silicon nitride (Si3N4) is sandwiched on both sides. The thickness of the protective layer was 150 nm on the substrate side and 200 nm on the reflective layer side. Gold (Au) is used as the reflective layer material,
The film thickness was 20 nm. Each layer was formed by a sputtering method. Table 3 shows the power range (optimum recording power range) in which the deterioration at the end of the recording area is 0.01 mm or less when the signal is recorded 10,000 times by overwriting under the recording conditions shown in Example 1. It is shown. (Table 4) also lists the melting point of the oxide selected as the inactive layer material and the standard free energy of formation at 1000°C.
【００４０】[0040]
【表３】[Table 3]
【００４１】（表３）より、記録薄膜に接して設けた不
活性層が、１０００゜Ｃにおける標準生成自由エネルギ
ーが−９００ｋＪ／ｍｏｌ Ｏ２よりも小さい酸化物か
らなる場合に、良好な繰り返し記録・消去が行える記録
パワー範囲が拡大することがわかる。不活性層は、複数
の酸化物から構成されていても差し支えない。しかし不
活性層を２０ｎｍより厚くすると繰り返しによって記録
薄膜が破れやすくなった。すなわち酸化物不活性層の膜
厚は２０ｎｍ以下が適当である。又、Ｇｅ２Ｓｂ２Ｔｅ
５記録薄膜の片側に熱的に安定な不活性層を設けた場合
でも、繰り返し特性の向上が見られた。From (Table 3), when the inert layer provided in contact with the recording thin film is made of an oxide whose standard free energy of formation at 1000°C is less than -900 kJ/mol O2, good repeated recording and It can be seen that the recording power range in which erasing can be performed is expanded. The inactive layer may be composed of a plurality of oxides. However, when the inactive layer was made thicker than 20 nm, the recording thin film became more likely to break due to repeated recording. That is, the thickness of the oxide inactive layer is suitably 20 nm or less. Also, Ge2Sb2Te
5. Even when a thermally stable inert layer was provided on one side of the recording thin film, the repeatability was improved.
【００４２】さらに記録薄膜の組成範囲を広げて、結晶
化・非晶質化感度がともに良好で、かつ記録薄膜に接し
て不活性層を設けることによって繰り返し特性が向上す
るような構成を調べた。実験の結果、結晶化・非晶質化
感度がともに良好（単一ビームによる重ね書きを考慮し
て、結晶化に必要な加熱時間が１００ｎｓｅｃ以下）で
、かつ記録・消去の繰り返し時に記録領域終端部劣化が
生じにくい構成は、Ｇｅ−Ｓｂ−Ｔｅ主成分の組成範囲
が、（Ｇｅ）ｘ（Ｓｂ）ｙ（Ｔｅ）ｚ
０．１０≦ｘ≦０．３５ ０．１０≦ｙ０．４５
≦ｚ≦０．６５ ｘ＋ｙ＋ｚ＝１で、かつ不活性
層が１０００゜Ｃにおける標準生成自由エネルギーが−
９００ｋＪ／ｍｏｌ Ｏ２よりも小さい酸化物よりなる
場合であることがわかった。又、不活性層の膜厚を２０
ｎｍ以下にすることで、繰り返し記録による記録薄膜に
ダメージを極めて小さくできることもあわせて確認され
た。Furthermore, by expanding the composition range of the recording thin film, we investigated a structure in which both crystallization and amorphization sensitivity are good, and the repetition characteristics are improved by providing an inert layer in contact with the recording thin film. . As a result of experiments, both crystallization and amorphization sensitivity were good (heating time required for crystallization was 100 ns or less considering overwriting by a single beam), and the end of the recording area was detected during repeated recording and erasing. The composition range of the main component of Ge-Sb-Te is (Ge)x(Sb)y(Te)z 0.10≦x≦0.35 0.10≦y0.45
≦z≦0.65 When x+y+z=1 and the inactive layer is at 1000°C, the standard free energy of formation is -
It was found that this is the case when the oxide is smaller than 900 kJ/mol O2. Also, the thickness of the inactive layer is 20
It was also confirmed that damage to the recording thin film caused by repeated recording can be minimized by making the thickness less than nm.
【００４３】記録薄膜主成分のＧｅ−Ｓｂ−Ｔｅ組成範
囲をさらに詳しく検討した結果、
（Ｇｅ２Ｓｂ２Ｔｅ５）ｘ（ＧｅＳｂ２Ｔｅ４）１−ｘ
０≦ｘ≦１
で表わされる範囲の記録薄膜組は、とりわけ結晶化速度
が速いと同時に、繰り返した時に記録・消去に伴う記録
領域終端部の劣化が顕著であった。結晶化速度が速いこ
とは重ね書き可能な相変化型光ディスクにとって非常に
好ましいことである。それ故、記録薄膜に接して不活性
層（熱的に安定な酸化物薄膜）を設けることによる繰り
返し劣化の抑制効果は、
（Ｇｅ２Ｓｂ２Ｔｅ５）ｘ（ＧｅＳｂ２Ｔｅ４）１−ｘ
０≦ｘ≦１
組成において顕著、かつ重要である。As a result of a more detailed study of the Ge-Sb-Te composition range of the main component of the recording thin film, we found that (Ge2Sb2Te5)x(GeSb2Te4)1-x
The recording thin film set in the range expressed by 0≦x≦1 had a particularly fast crystallization speed, and at the same time, the deterioration of the end portion of the recording area due to repeated recording and erasing was remarkable. A high crystallization rate is highly desirable for a rewritable phase change optical disc. Therefore, the effect of suppressing repeated deterioration by providing an inert layer (thermally stable oxide thin film) in contact with the recording thin film is as follows: (Ge2Sb2Te5)x(GeSb2Te4)1-x
0≦x≦1 Significant and important in composition.
【００４４】実施例５
実施例４では、Ｇｅ−Ｓｂ−Ｔｅ記録薄膜の両側、或は
片側に熱的に安定な酸化物、すなわち１０００゜Ｃにお
ける標準生成自由エネルギーが−９００ｋＪ／ｍｏｌ
Ｏ２よりも小さい酸化物、からなる不活性層を設けるこ
とによって、記録・消去の繰り返し特性が向上すること
を示した。他にも、Ｔｅ或はＩｎを主成分とする記録薄
膜、例えばＴｅ−Ｇｅ，Ｔｅ−Ｇｅ−Ｓｎ，Ｔｅ−Ｇｅ
−Ｓｎ−Ａｕ，Ｓｂ−Ｔｅ，Ｓｂ−Ｓｅ−Ｔｅ，Ｉｎ−
Ｔｅ，Ｉｎ−Ｓｅ，Ｉｎ−Ｓｅ−Ｔｌ，Ｉｎ−Ｓｂ，Ｉ
ｎ−Ｓｂ−Ｓｅ，Ｉｎ−Ｓｅ−Ｔｅ記録薄膜の両側、或
は片側に熱的に安定な酸化物（具体的には１０００゜Ｃ
における標準生成自由エネルギーが−９００ｋＪ／ｍｏ
ｌ Ｏ２よりも小さい酸化物）からなる不活性層を設け
ることによって、いずれも記録・消去繰り返し時の記録
領域終端部劣化が生じにくくなる傾向があることを実験
で確かめた。不活性層は複数種の酸化物から構成されて
いても差し支えないことも実験より確認された。Example 5 In Example 4, a thermally stable oxide was used on both sides or one side of the Ge-Sb-Te recording thin film, that is, the standard free energy of formation at 1000°C was -900 kJ/mol.
It was shown that the repeated recording/erasing characteristics were improved by providing an inactive layer made of an oxide smaller than O2. In addition, recording thin films mainly composed of Te or In, such as Te-Ge, Te-Ge-Sn, Te-Ge
-Sn-Au, Sb-Te, Sb-Se-Te, In-
Te, In-Se, In-Se-Tl, In-Sb, I
A thermally stable oxide (specifically, 1000°C
The standard free energy of formation is -900 kJ/mo
It has been experimentally confirmed that by providing an inactive layer made of an oxide smaller than lO2, deterioration at the end of the recording area tends to be less likely to occur during repeated recording and erasing. It was also confirmed through experiments that the inert layer may be composed of multiple types of oxides.
【００４５】本実施例，及び実施例３を組み合わせる、
すなわち記録薄膜材料成分に熱的に安定な酸化物を添加
し、かつ記録薄膜の両側、或は片側に熱的に安定な酸化
物からなる不活性層を設けることによっても、記録・消
去の繰り返し時の記録領域終端部劣化が抑制される。[0045] Combining this example and Example 3,
That is, by adding a thermally stable oxide to the recording thin film material and providing an inert layer made of a thermally stable oxide on both sides or one side of the recording thin film, it is possible to repeat recording and erasing. Deterioration at the end of the recording area is suppressed.
【００４６】実施例６
実施例４で、Ｇｅ２Ｓｂ２Ｔｅ５記録薄膜の両側、或は
片側に熱的に安定な酸化物からなる不活性層を設けるこ
とによって、記録・消去の繰り返し時の記録領域終端部
劣化が抑制されることを示した。そこで次に、酸化物不
活性層を設けることなしに、記録薄膜に接する保護層の
材料成分に熱的に安定な酸化物混ぜ込むことによって、
繰り返しにおける記録領域終端部劣化が抑制されるかを
、保護層母材及び添加する酸化材の種類を種々変えて調
べた。Example 6 In Example 4, by providing an inactive layer made of a thermally stable oxide on both sides or one side of the Ge2Sb2Te5 recording thin film, deterioration at the end of the recording area during repeated recording and erasing was prevented. was shown to be suppressed. Therefore, without providing an oxide inactive layer, by incorporating a thermally stable oxide into the material components of the protective layer in contact with the recording thin film,
It was investigated whether the deterioration of the end portion of the recording area due to repetition could be suppressed by varying the base material of the protective layer and the type of oxidizing agent added.
【００４７】一例として、（表４）にＧｅ２Ｓｂ２Ｔｅ
５記録薄膜の両側に、母材が窒化ケイ素で、種々の酸化
物を混ぜ込んで形成した保護層を設けた光ディスクの繰
り返し特性を示す。この時のディスクの構造を図１に示
す。基板の材質は５．２５インチ径のガラスとした。記
録薄膜の膜厚は６０ｎｍで、その両側を、窒化ケイ素を
母材としてさらに酸化物が添加された保護層がサンドイ
ッチしている。保護層の膜厚は、基板側の膜厚が１５０
ｎｍ、記録薄膜上が２００ｎｍである。反射層材料には
金（Ａｕ）を用い、膜厚は２０ｎｍとした。各層の形成
はスパタリング法により行った。特に保護層の成膜は、
窒化ケイ素（母材）ターゲットと、添加材となる酸化物
のターゲットを用意し、共スパタリング法によって、母
材中に占める酸化物の割合が８０ｗｔ％となるようにし
た。実施例１に示した記録条件で、重ね書きで信号を１
万回記録した場合に、記録領域終端部の劣化が０．０１
ｍｍ以下となるパワー領域（最適記録パワー範囲）を（
表４）に示してある。
（表４）には、保護層への添加材料に選んだ酸化物の融
点、及び１０００゜Ｃにおける標準生成自由エネルギー
を併記した。As an example, (Table 4) shows Ge2Sb2Te.
5 shows the repeating characteristics of an optical disk in which a protective layer made of silicon nitride as a base material and mixed with various oxides is provided on both sides of a recording thin film. The structure of the disk at this time is shown in FIG. The material of the substrate was glass with a diameter of 5.25 inches. The thickness of the recording thin film is 60 nm, and a protective layer made of silicon nitride as a base material and further added with an oxide is sandwiched on both sides thereof. The thickness of the protective layer is 150 mm on the substrate side.
nm, and the thickness on the recording thin film is 200 nm. Gold (Au) was used as the reflective layer material, and the film thickness was 20 nm. Each layer was formed by a sputtering method. Especially when forming a protective layer,
A silicon nitride (base material) target and an oxide target as an additive were prepared, and a co-sputtering method was used so that the proportion of the oxide in the base material was 80 wt%. Under the recording conditions shown in Example 1, one signal was recorded by overwriting.
Deterioration at the end of the recording area is 0.01 after 10,000 recordings.
The power range (optimum recording power range) below mm is (
Table 4). (Table 4) also lists the melting points and standard free energies of formation at 1000°C of the oxides selected as additives to the protective layer.
【００４８】[0048]
【表４】[Table 4]
【００４９】（表４）より、１０００゜Ｃにおける標準
生成自由エネルギーが−９００ｋＪ／ｍｏｌＯ２よりも
小さい酸化物を、記録薄膜に接して設けた保護層中に添
加した場合に、良好な繰り返し記録・消去が行える記録
パワー範囲が拡大することがわかる。保護層への添加物
は、複数の酸化物から構成されていても差し支えない。
又、Ｇｅ２Ｓｂ２Ｔｅ５記録薄膜の片側にのみ、熱的に
安定な酸化物を混入した保護層を設けた場合でも、繰り
返し特性の向上が見られた。From (Table 4), when an oxide whose standard free energy of formation at 1000°C is less than -900 kJ/molO2 is added to the protective layer provided in contact with the recording thin film, good repeated recording and It can be seen that the recording power range in which erasing can be performed is expanded. The additive to the protective layer may be composed of multiple oxides. Further, even when a protective layer containing a thermally stable oxide was provided on only one side of the Ge2Sb2Te5 recording thin film, the repeatability was improved.
【００５０】さらに記録薄膜の組成範囲を広げて、結晶
化・非晶質化感度がともに良好で、かつ記録薄膜に接し
て熱的に安定な酸化物を混ぜ込んだ保護層を設けること
によって繰り返し特性が向上するような構成を調べた。
実験の結果、結晶化・非晶質化感度がともに良好（単一
ビームによる重ね書きを考慮して、結晶化に必要な加熱
時間が１００ｎｓｅｃ以下）で、かつ記録・消去の繰り
返し時に記録領域終端部劣化が生じにくい構成は、Ｇｅ
−Ｓｂ−Ｔｅ主成分の組成範囲が、
（Ｇｅ）ｘ（Ｓｂ）ｙ（Ｔｅ）ｚ
０．１０≦ｘ≦０．３５ ０．１０≦ｙ０．４５
≦ｚ≦０．６５ ｘ＋ｙ＋ｚ＝１で、かつ保護層
の添加材が、１０００゜Ｃにおける標準生成自由エネル
ギーが−９００ｋＪ／ｍｏｌ Ｏ２よりも小さい酸化物
、の場合であることがわかった。Furthermore, by widening the composition range of the recording thin film and providing a protective layer containing a thermally stable oxide that has good sensitivity to both crystallization and amorphization, and in contact with the recording thin film, repeated recording can be performed. We investigated configurations that would improve characteristics. As a result of experiments, both crystallization and amorphization sensitivity were good (heating time required for crystallization was 100 ns or less considering overwriting by a single beam), and the end of the recording area was detected during repeated recording and erasing. The structure in which part deterioration is less likely to occur is
-Sb-Te main component composition range is (Ge)x(Sb)y(Te)z 0.10≦x≦0.35 0.10≦y0.45
≦z≦0.65 x+y+z=1, and it was found that the additive material of the protective layer is an oxide whose standard free energy of formation at 1000°C is smaller than -900 kJ/mol O2.
【００５１】記録薄膜主成分のＧｅ−Ｓｂ−Ｔｅ組成範
囲をさらに詳しく検討した結果、
（Ｇｅ２Ｓｂ２Ｔｅ５）ｘ（ＧｅＳｂ２Ｔｅ４）１−ｘ
０≦ｘ≦１
で表わされる範囲の記録薄膜組は、とりわけ結晶化速度
が速いと同時に、繰り返しに記録・消去に伴う記録領域
終端部の劣化が顕著であった。結晶化速度が速いことは
重ね書き可能な相変化型光ディスクにとって非常に好ま
しいことである。それ故、保護層に熱的に安定な酸化物
を添加することによる繰り返し劣化の抑制効果は、（Ｇ
ｅ２Ｓｂ２Ｔｅ５）ｘ（ＧｅＳｂ２Ｔｅ４）１−ｘ０≦
ｘ≦１
組成において顕著、かつ重要である。As a result of a more detailed study of the Ge-Sb-Te composition range of the main component of the recording thin film, (Ge2Sb2Te5)x(GeSb2Te4)1-x
The recording thin film set in the range expressed by 0≦x≦1 had a particularly fast crystallization speed, and at the same time, the deterioration at the end of the recording area due to repeated recording and erasing was remarkable. A high crystallization rate is highly desirable for a rewritable phase change optical disc. Therefore, the effect of suppressing repeated deterioration by adding a thermally stable oxide to the protective layer is
e2Sb2Te5)x(GeSb2Te4)1-x0≦
x≦1 Significant and important in composition.
【００５２】さらに、保護層に添加する酸化物の適量を
実験により明らかにした。添加する酸化物としてＧｄ２
Ｏ３，Ｈｏ２Ｏ３，Ｌａ２Ｏ３，Ｎｄ２Ｏ３，Ｓｃ２Ｏ
３，Ｓｍ２Ｏ３，ＳｒＯ，Ｔｂ２Ｏ３，ＴｈＯ２，Ｙ２
Ｏ３を選んで実験を行なったが、いずれの場合も、保護
層中に占める酸化物の割合が少なくとも５０ｗｔ％以上
でないと、十分な繰り返し劣化の抑制効果が得られない
ことがわかった。このことより、熱的に安定な酸化物、
具体的には、１０００゜Ｃにおける標準生成自由エネル
ギーが−９００ｋＪ／ｍｏｌＯ２よりも小さい酸化物、
を少なくとも５０ｗｔ％の割合で保護層中に含ませた場
合に、繰り返し劣化が抑制されると判断できる。Furthermore, the appropriate amount of oxide to be added to the protective layer was clarified through experiments. Gd2 as an oxide to add
O3, Ho2O3, La2O3, Nd2O3, Sc2O
3, Sm2O3, SrO, Tb2O3, ThO2, Y2
Experiments were conducted with O3 selected, and in all cases it was found that unless the proportion of oxide in the protective layer was at least 50 wt %, a sufficient effect of suppressing repeated deterioration could not be obtained. From this, thermally stable oxides,
Specifically, oxides whose standard free energy of formation at 1000°C is less than -900 kJ/molO2,
It can be determined that repeated deterioration is suppressed when the protective layer contains at least 50 wt % of .
【００５３】又、保護層の母材は窒化ケイ素に限定する
必要はない。例えば、Ａｌ２Ｏ３，ＳｉＯｘ，Ｔａ２Ｏ
５，ＭｏＯ３，ＷＯ３，ＺｎＳ，ＺｒＯ２，ＡｌＮｘ，
ＢＮ，ＴｉＮ，ＺｒＮ，ＰｂＦ２，ＭｇＦ２等の誘電体
或はこれらの適当な組み合わせからなる保護層に対して
も、熱的に安定な酸化物を添加することによって記録・
消去の繰り返し特性を向上させることができる。Furthermore, the base material of the protective layer does not need to be limited to silicon nitride. For example, Al2O3, SiOx, Ta2O
5, MoO3, WO3, ZnS, ZrO2, AlNx,
By adding a thermally stable oxide to a protective layer made of a dielectric material such as BN, TiN, ZrN, PbF2, MgF2, or a suitable combination thereof, recording and recording can be achieved.
Erasing repeatability can be improved.
【００５４】又、熱的に安定な酸化物を保護層全体に均
一に分散させる必要はない。重要なのは、記録薄膜との
界面付近に熱的に安定な酸化物が存在することである。Also, it is not necessary to uniformly disperse the thermally stable oxide throughout the protective layer. What is important is that a thermally stable oxide exists near the interface with the recording thin film.
【００５５】実施例７
実施例６では、Ｇｅ−Ｓｂ−Ｔｅ記録薄膜の両側、或は
片側に熱的に安定な酸化物、すなわち１０００゜Ｃにお
ける標準生成自由エネルギーが−９００ｋＪ／ｍｏｌ
Ｏ２よりも小さい酸化物、を含む保護層を設けることに
よって、記録・消去の繰り返し特性が向上することを示
した。他にも、Ｔｅ或はＩｎを主成分とする記録薄膜、
例えばＴｅ−Ｇｅ，Ｔｅ−Ｇｅ−Ｓｎ，Ｔｅ−Ｇｅ−Ｓ
ｎ−Ａｕ，Ｓｂ−Ｔｅ，Ｓｂ−Ｓｅ−Ｔｅ，Ｉｎ−Ｔｅ
，Ｉｎ−Ｓｅ，Ｉｎ−Ｓｅ−Ｔｌ，Ｉｎ−Ｓｂ，Ｉｎ−
Ｓｂ−Ｓｅ，Ｉｎ−Ｓｅ−Ｔｅ記録薄膜の両側、或は片
側に熱的に安定な酸化物（具体的には１０００゜Ｃにお
ける標準生成自由エネルギーが−９００ｋＪ／ｍｏｌ
Ｏ２よりも小さい酸化物）を含む保護層を設けることに
よって、いずれも記録・消去繰り返し時の記録領域終端
部劣化が生じにくくなる傾向があることを実験で確かめ
た。保護層へ添加する熱的に安定な酸化物が複数種であ
っても差し支えないことも、実験によって確認された。Example 7 In Example 6, a thermally stable oxide was used on both sides or one side of the Ge-Sb-Te recording thin film, that is, the standard free energy of formation at 1000°C was -900 kJ/mol.
It was shown that the repeated recording/erasing characteristics were improved by providing a protective layer containing an oxide smaller than O2. In addition, recording thin films mainly composed of Te or In,
For example, Te-Ge, Te-Ge-Sn, Te-Ge-S
n-Au, Sb-Te, Sb-Se-Te, In-Te
, In-Se, In-Se-Tl, In-Sb, In-
A thermally stable oxide (specifically, the standard free energy of formation at 1000°C is -900 kJ/mol on both sides or one side of the Sb-Se, In-Se-Te recording thin film)
It has been experimentally confirmed that by providing a protective layer containing an oxide smaller than O2, deterioration at the end of the recording area tends to be less likely to occur during repeated recording and erasing. It has also been confirmed through experiments that there is no problem even if multiple types of thermally stable oxides are added to the protective layer.
【００５６】ここでも、実施例６同様に、熱的に安定な
酸化物、具体的には１０００゜Ｃにおける標準生成自由
エネルギーが−９００ｋＪ／ｍｏｌ Ｏ２よりも小さい
酸化物、を少なくとも５０ｗｔ％の割合で保護層中に含
ませた場合に、繰り返し劣化が抑制されることがわかっ
た。Here, as in Example 6, at least 50 wt% of a thermally stable oxide, specifically an oxide whose standard free energy of formation at 1000°C is smaller than -900 kJ/mol O2, is used. It was found that repeated deterioration was suppressed when the compound was included in the protective layer.
【００５７】本実施例，及び実施例３を組み合わせる、
すなわち記録薄膜材料成分に熱的に安定な酸化物を添加
し、かつ記録薄膜の両側、或は片側に熱的に安定な酸化
物を含む保護層を設けることによっても、記録・消去の
繰り返し時の記録領域終端部劣化が抑制されることが確
認された。[0057] Combining this example and Example 3,
That is, by adding a thermally stable oxide to the recording thin film material and providing a protective layer containing a thermally stable oxide on both sides or one side of the recording thin film, it is possible to prevent repeated recording and erasing. It was confirmed that deterioration at the end of the recording area was suppressed.
【００５８】[0058]
【発明の効果】１０００゜Ｃにおける標準生成自由エネ
ルギーが−９００ｋＪ／ｍｏｌ Ｏ２よりも小さい酸化
物を記録薄膜中に加える、或は記録薄膜界面に設けるこ
とにより、良好な繰り返し特性が得られる記録パワ−の
許容範囲が拡大する。Effects of the Invention: By adding an oxide whose standard free energy of formation at 1000°C is less than -900 kJ/mol O2 into the recording thin film or providing it at the interface of the recording thin film, a recording power with good repeatability can be obtained. − The permissible range is expanded.
【図１】本発明の実施例の記録媒体の構造を示す断面図
である。FIG. 1 is a sectional view showing the structure of a recording medium according to an embodiment of the present invention.
【図２】Ｇｅ２Ｓｂ２Ｔｅ５−Ｇｄ２Ｏ３記録薄膜を有
するディスクの、記録薄膜に占めるＧｄ２Ｏ３の重量比
と消去率の関係を示す図である。FIG. 2 is a diagram showing the relationship between the weight ratio of Gd2O3 in the recording thin film and the erasure rate of a disk having a Ge2Sb2Te5-Gd2O3 recording thin film.
【図３】Ｇｅ−Ｓｂ−Ｔｅを主成分とする記録薄膜の主
成分組成範囲を示す図である。FIG. 3 is a diagram showing the main component composition range of a recording thin film whose main component is Ge-Sb-Te.
【図４】本発明の実施例の記録媒体の構造を示す断面図
である。FIG. 4 is a cross-sectional view showing the structure of a recording medium according to an embodiment of the present invention.
１ 基板 ２ 保護層 ３ 記録薄膜 ４ 保護層 ５ 反射層 ６ 接着層 ７ 保護基板 ８ 基板平面 ９ 不活性層 1 Board 2 Protective layer 3 Recording thin film 4 Protective layer 5 Reflective layer 6 Adhesive layer 7 Protective board 8 Substrate plane 9 Inactive layer
Claims (16)
ザ光線の照射により相変化を生じて光学特性の異なる状
態へと可逆的に移り得る記録薄膜とを少なくとも備えて
なる光学情報記録媒体において、前記記録薄膜が酸化物
を含有し、かつ前記酸化物の１０００゜Ｃにおける標準
生成自由エネルギーが−９００ｋＪ／ｍｏｌ Ｏ２より
も小さいことを特徴とする光学情報記録媒体。1. An optical information recording medium comprising at least a substrate and a recording thin film formed on the substrate and capable of causing a phase change upon irradiation with a laser beam and reversibly transitioning to a state with different optical properties. . An optical information recording medium, wherein the recording thin film contains an oxide, and the standard free energy of formation of the oxide at 1000°C is smaller than -900 kJ/mol O2.
２Ｏ３，Ｈｏ２Ｏ３，Ｌａ２Ｏ３，Ｎｄ２Ｏ３，Ｓｃ２
Ｏ３，Ｓｍ２Ｏ３，ＳｒＯ，Ｔｂ２Ｏ３，ＴｈＯ２，Ｙ
２Ｏ３の１０種類の酸化物のいずれか１種類、或はこれ
ら酸化物の組合せであることを特徴とする請求項１項記
載の光学情報記録媒体。Claim 2: The oxide contained in the recording thin film is Gd
2O3, Ho2O3, La2O3, Nd2O3, Sc2
O3, Sm2O3, SrO, Tb2O3, ThO2, Y
2. The optical information recording medium according to claim 1, wherein the optical information recording medium is any one of ten types of oxides of 2O3 or a combination of these oxides.
あることを特徴とする請求項１項記載の光学情報記録媒
体。3. The optical information recording medium according to claim 1, wherein the main component of the recording thin film is Te or In.
で、主成分の組成比が、 （Ｇｅ）ｘ（Ｓｂ）ｙ（Ｔｅ）ｚ ０．１０≦ｘ≦０．３５ ０．１０≦ｙ０．４５
≦ｚ≦０．６５ ｘ＋ｙ＋ｚ＝１で表わされる範
囲内にあり、かつ前記主成分が記録薄膜に占める割合が
９０ｗｔ％以上であることを特徴とする請求項１項記載
の光学情報記録媒体。[Claim 4] The main components of the recording thin film are Ge, Sb, and Te.
The composition ratio of the main components is (Ge)x(Sb)y(Te)z 0.10≦x≦0.35 0.10≦y0.45
2. The optical information recording medium according to claim 1, wherein the main component is within the range expressed by ≦z≦0.65 x+y+z=1, and the proportion of the main component in the recording thin film is 90 wt% or more.
２Ｓｂ２Ｔｅ５）ｘ（ＧｅＳｂ２Ｔｅ４）１−ｘ０≦ｘ
≦１ で表わされる範囲内にあることを特徴とする請求項４項
記載の光学情報記録媒体。5. The composition ratio of Ge, Sb, and Te is (Ge
2Sb2Te5)x(GeSb2Te4)1-x0≦x
5. The optical information recording medium according to claim 4, wherein the optical information recording medium is within the range expressed by ≦1.
ザ光線の照射により相変化を生じて光学特性の異なる状
態へと可逆的に移り得る記録薄膜と、前記記録薄膜に接
してその両側、或は片側に形成した不活性層とを少なく
とも備えてなる光学情報記録媒体において、前記不活性
層が、１０００゜Ｃにおける標準生成自由エネルギーが
−９００ｋＪ／ｍｏｌ Ｏ２よりも小さい酸化物からな
ることを特徴とする光学情報記録媒体。6. A substrate, a recording thin film formed on the substrate and capable of reversibly changing to a state with different optical properties by causing a phase change upon irradiation with a laser beam, and contacting the recording thin film on both sides thereof; Alternatively, in an optical information recording medium comprising at least an inactive layer formed on one side, the inactive layer is made of an oxide having a standard free energy of formation at 1000°C smaller than -900 kJ/mol O2. Characteristic optical information recording media.
Ｏ３，Ｈｏ２Ｏ３，Ｌａ２Ｏ３，Ｎｄ２Ｏ３，Ｓｃ２Ｏ
３，Ｓｍ２Ｏ３，ＳｒＯ，Ｔｂ２Ｏ３，ＴｈＯ２，Ｙ２
Ｏ３の１０種類の酸化物のいずれか１種類、或はこれら
酸化物の組合せであることを特徴とする請求項６項記載
の光学情報記録媒体。7. The oxide forming the inactive layer is Gd2
O3, Ho2O3, La2O3, Nd2O3, Sc2O
3, Sm2O3, SrO, Tb2O3, ThO2, Y2
7. The optical information recording medium according to claim 6, wherein the optical information recording medium is any one of ten types of oxides of O3 or a combination of these oxides.
あることを特徴とする請求項６項記載の光学情報記録媒
体。8. The optical information recording medium according to claim 6, wherein the main component of the recording thin film is Te or In.
で、主成分の組成比が、 （Ｇｅ）ｘ（Ｓｂ）ｙ（Ｔｅ）ｚ ０．１０≦ｘ≦０．３５ ０．１０≦ｙ０．４５
≦ｚ≦０．６５ ｘ＋ｙ＋ｚ＝１で表わされる範
囲内にあることを特徴とする請求項６項記載の光学情報
記録媒体。[Claim 9] The main components of the recording thin film are Ge, Sb, and Te.
The composition ratio of the main components is (Ge)x(Sb)y(Te)z 0.10≦x≦0.35 0.10≦y0.45
7. The optical information recording medium according to claim 6, wherein the optical information recording medium is within the range expressed by ≦z≦0.65 x+y+z=1.
ｅ２Ｓｂ２Ｔｅ５）ｘ（ＧｅＳｂ２Ｔｅ４）１−ｘ０≦
ｘ≦１ で表わされる範囲内にあることを特徴とする請求項９項
記載の光学情報記録媒体。10. The composition ratio of Ge, Sb, and Te is (G
e2Sb2Te5)x(GeSb2Te4)1-x0≦
10. The optical information recording medium according to claim 9, wherein x is within the range expressed by x≦1.
ることを特徴とする請求項６項記載の光学情報記録媒体
。11. The optical information recording medium according to claim 6, wherein the inactive layer has a thickness of 20 nm or less.
ーザ光線の照射により相変化を生じて光学特性の異なる
状態へと可逆的に移り得る記録薄膜と、前記記録薄膜の
両側、或はその片側に接して形成した保護層を備えてな
る光学情報記録媒体において、上記保護層が、１０００
゜Ｃにおける標準生成自由エネルギーが−９００ｋＪ／
ｍｏｌ Ｏ２よりも小さい酸化物を含有し、その含有量
が５０ｗｔ％以上であることを特徴とする光学情報記録
媒体。12. A substrate, a recording thin film formed on the substrate and capable of reversibly transitioning to a state with different optical properties by causing a phase change upon irradiation with a laser beam, and a recording thin film formed on both sides of the recording thin film or the recording thin film. In an optical information recording medium comprising a protective layer formed in contact with one side, the protective layer has a
The standard free energy of formation at °C is -900 kJ/
An optical information recording medium characterized in that it contains an oxide smaller than mol O2, and the content thereof is 50 wt% or more.
２Ｏ３，Ｈｏ２Ｏ３，Ｌａ２Ｏ３，Ｎｄ２Ｏ３，Ｓｃ２
Ｏ３，Ｓｍ２Ｏ３，ＳｒＯ，Ｔｂ２Ｏ３，ＴｈＯ２，Ｙ
２Ｏ３の１０種類の酸化物のいずれか１種類、或はこれ
ら酸化物の組合せであることを特徴とする請求項１２項
記載の光学情報記録媒体。13. The oxide contained in the protective layer is Gd
2O3, Ho2O3, La2O3, Nd2O3, Sc2
O3, Sm2O3, SrO, Tb2O3, ThO2, Y
13. The optical information recording medium according to claim 12, wherein the optical information recording medium is any one of ten types of oxides of 2O3 or a combination of these oxides.
であることを特徴とする請求項１２項記載の光学情報記
録媒体。14. The main component of the recording thin film is Te or In.
The optical information recording medium according to claim 12, characterized in that:
ｅで、主成分の組成比が、 （Ｇｅ）ｘ（Ｓｂ）ｙ（Ｔｅ）ｚ ０．１０≦ｘ≦０．３５ ０．１０≦ｙ０．４５
≦ｚ≦０．６５ ｘ＋ｙ＋ｚ＝１で表わされる範
囲内にあることを特徴とする請求項１２項記載の光学情
報記録媒体。[Claim 15] The main components of the recording thin film are Ge, Sb, and T.
e, the composition ratio of the main components is (Ge)x(Sb)y(Te)z 0.10≦x≦0.35 0.10≦y0.45
13. The optical information recording medium according to claim 12, wherein the optical information recording medium is within the range expressed by ≦z≦0.65 x+y+z=1.
ｅ２Ｓｂ２Ｔｅ５）ｘ（ＧｅＳｂ２Ｔｅ４）１−ｘ０≦
ｘ≦１ で表される範囲内にあることを特徴とする請求項１５項
記載の光学情報記録媒体。16. The composition ratio of Ge, Sb, and Te is (G
e2Sb2Te5)x(GeSb2Te4)1-x0≦
16. The optical information recording medium according to claim 15, wherein x is within the range expressed by x≦1.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP09579791A JP3151848B2 (en) | 1991-04-25 | 1991-04-25 | Optical information recording medium |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP09579791A JP3151848B2 (en) | 1991-04-25 | 1991-04-25 | Optical information recording medium |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH04325288A true JPH04325288A (en) | 1992-11-13 |
| JP3151848B2 JP3151848B2 (en) | 2001-04-03 |
Family
ID=14147435
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP09579791A Expired - Fee Related JP3151848B2 (en) | 1991-04-25 | 1991-04-25 | Optical information recording medium |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3151848B2 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2000006391A1 (en) * | 1998-07-31 | 2000-02-10 | Hitachi Maxell, Ltd. | Information recording medium and information recording method |
| WO2004085167A1 (en) * | 2003-03-24 | 2004-10-07 | Matsushita Electric Industrial Co., Ltd. | Information recording medium and method for manufacturing same |
| US7050377B1 (en) | 1999-05-19 | 2006-05-23 | Mitsubishi Chemical Corporation | Optical recording method and optical recording medium |
-
1991
- 1991-04-25 JP JP09579791A patent/JP3151848B2/en not_active Expired - Fee Related
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2000006391A1 (en) * | 1998-07-31 | 2000-02-10 | Hitachi Maxell, Ltd. | Information recording medium and information recording method |
| US7050377B1 (en) | 1999-05-19 | 2006-05-23 | Mitsubishi Chemical Corporation | Optical recording method and optical recording medium |
| US7085215B2 (en) | 1999-05-19 | 2006-08-01 | Mitsubishi Kagaku Media Co., Ltd. | Optical recording method and optical recording medium |
| USRE42786E1 (en) | 1999-05-19 | 2011-10-04 | Mitsubishi Kagaku Media Co., Ltd. | Optical recording method and optical recording medium |
| USRE45001E1 (en) | 1999-05-19 | 2014-07-08 | Mitsubishi Kagaku Media Co., Ltd. | Optical recording method and optical recording medium |
| WO2004085167A1 (en) * | 2003-03-24 | 2004-10-07 | Matsushita Electric Industrial Co., Ltd. | Information recording medium and method for manufacturing same |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3151848B2 (en) | 2001-04-03 |
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