JP2571556B2 - Optical information recording medium - Google Patents
Optical information recording mediumInfo
- Publication number
- JP2571556B2 JP2571556B2 JP62326884A JP32688487A JP2571556B2 JP 2571556 B2 JP2571556 B2 JP 2571556B2 JP 62326884 A JP62326884 A JP 62326884A JP 32688487 A JP32688487 A JP 32688487A JP 2571556 B2 JP2571556 B2 JP 2571556B2
- Authority
- JP
- Japan
- Prior art keywords
- thin film
- content
- gete
- recording medium
- optical information
- 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.)
- Expired - Fee Related
Links
Landscapes
- Thermal Transfer Or Thermal Recording In General (AREA)
- Optical Record Carriers And Manufacture Thereof (AREA)
Description
【発明の詳細な説明】 〔産業上の利用分野〕 本発明は、光ビームを用いて情報が記録再生される光
記録媒体に関するものである。Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical recording medium on which information is recorded and reproduced using a light beam.
テルル化ゲルマニウム（GeTe）は、光記録材料として
記録感度が高く、再生信号の信号体雑音比を大きくする
ことができる好適な材料である。Germanium telluride (GeTe) is a suitable material as an optical recording material that has high recording sensitivity and can increase the signal-to-noise ratio of a reproduced signal.
さて、光情報記録媒体は、データの長期保存の目的に
使用されることがあり、高温高湿の環境下に放置されて
も記録材料の変化がなく、記録データを正確に読み書き
できることが必要である。Optical information recording media are sometimes used for long-term storage of data, and it is necessary that there is no change in the recording material even when left in a high-temperature, high-humidity environment, and that the recorded data can be read and written accurately. is there.
GeTe材料はかかる点についてみると、その薄膜が高温
高湿の環境下において徐々にではあるが酸化腐食し、反
射率や透過率という光学的性質が変化する現象がある。In view of this point, the GeTe material has a phenomenon that its thin film is gradually oxidized and corroded in a high-temperature and high-humidity environment, and the optical properties such as reflectance and transmittance change.
この原因として、GeTe結晶は菱面体構造をしている
が、原子半径の小さい他の原子が侵入することのできる
すきまが存在することをあげることが出来る。即ち、非
晶質相のGeTe薄膜中のGe−Te結合原子間距離は、均一で
なく非常に広い分布をもつために、GeTe薄膜が高温高湿
の環境下におかれると、原子半径の小さい酸素がこのす
きまに侵入し、Ge−Te,Ge−Ge,Te−Te結合を切断し、Ge
O2,TeO2となって徐々に薄膜を酸化させる。The cause of this is that the GeTe crystal has a rhombohedral structure, but there is a gap into which other atoms having a small atomic radius can penetrate. That is, the distance between Ge-Te bond atoms in the amorphous phase GeTe thin film is not uniform, and has a very wide distribution.Therefore, when the GeTe thin film is placed in an environment of high temperature and high humidity, the atomic radius is small. Oxygen penetrates into this gap to break Ge--Te, Ge--Ge, Te--Te bonds,
O 2 and TeO 2 are formed and the thin film is gradually oxidized.
この為、従来は、GeTe薄膜に酸化物，窒化物等の無機
薄膜を被着させて保護膜とし、高温高湿環境下における
GeTe薄膜の劣化を防止していたが、上記保護膜作製に長
時間を要したり、光情報記録媒体作製工程の複雑化や媒
体製造価格の上昇を招くという欠点があった。For this reason, conventionally, an inorganic thin film such as an oxide or a nitride is applied to a GeTe thin film to form a protective film, which is used in a high-temperature, high-humidity environment.
Although the deterioration of the GeTe thin film was prevented, there were disadvantages that it took a long time to produce the above protective film, complicated the optical information recording medium production process, and increased the medium production price.
本出願人はこのような欠点を解消し、高温高湿環境下
に放置されても、正確に情報を記録再生できる光情報記
録媒体を提供し得る記録薄膜として、GeTe材料にAgを添
加した材料の記録薄膜を見出した。この様な、Agが添加
されたGeTe薄膜においては、Ag原子によってあらかじめ
Ge−Te格子内のすきまが埋められているため酸素は侵入
しにくく、また、わずかに侵入した酸素はAgと結合しAg
Oとなって安定するので、GeTe薄膜は酸素の侵入による
劣化から保護される。The present applicant has solved such a drawback, and a material obtained by adding Ag to a GeTe material as a recording thin film capable of providing an optical information recording medium capable of accurately recording and reproducing information even when left in a high temperature and high humidity environment. Was found. In such a GeTe thin film to which Ag is added, Ag atoms are used in advance.
Since the gaps in the Ge-Te lattice are buried, oxygen hardly penetrates, and the slightly penetrated oxygen combines with Ag to form Ag.
Since it becomes O and becomes stable, the GeTe thin film is protected from deterioration due to intrusion of oxygen.
ところが、上記Ag添加GeTe薄膜を光記録膜とする光情
報記録媒体は、寿命が長くなるものの、Ag含有量が増す
と徐々に信号対雑音比（CNR）が劣化し、Agが３原子パ
ーセント以上では信頼できる光情報記録媒体としての性
能が得難く、又、Ag含有量をへらしたのでは寿命があま
り延びないという問題があった。However, the optical information recording medium using the above-mentioned Ag-doped GeTe thin film as an optical recording film has a long life, but as the Ag content increases, the signal-to-noise ratio (CNR) gradually deteriorates, and the Ag content exceeds 3 atomic percent. However, there is a problem that it is difficult to obtain a reliable performance as an optical information recording medium, and the life is not extended much if the Ag content is reduced.
即ち、GeTe薄膜が記録光ビームの照射を受けて非晶質
相から結晶質相に転移すると、GeTe結合原子間距離の分
布は均一化され、Ag原子が結晶質相Ge−Te格子内に入り
得る量は制限され、非晶質相Ge−Te格子内にあったAg原
子がGeTe薄膜の結晶化によってGe−Te結晶格子外に排斥
されAgが析出する。従って、この析出したAgが再生光ビ
ームの反射率を変化させて雑音成分となりCNRを低下さ
せるものと思われる。That is, when the GeTe thin film undergoes a recording light beam irradiation and changes from an amorphous phase to a crystalline phase, the distribution of the distance between GeTe bonding atoms becomes uniform, and Ag atoms enter the crystalline phase Ge-Te lattice. The amount to be obtained is limited, and Ag atoms in the amorphous phase Ge-Te lattice are rejected out of the Ge-Te crystal lattice by crystallization of the GeTe thin film, and Ag is precipitated. Therefore, it is considered that the deposited Ag changes the reflectivity of the reproduction light beam, becomes a noise component, and lowers the CNR.
本発明は上記問題点を解決するために、該記録薄膜
を、Agが添加されたGeTeを主成分とする薄膜とし、該光
記録薄膜中のAg含有量を基体側においては平均Ag含有量
よりも小さくし保護膜側においては平均Ag含有量よりも
大きくした。The present invention, in order to solve the above problems, the recording thin film, a thin film containing Ge as a main component to which Ag is added, the Ag content in the optical recording thin film on the substrate side from the average Ag content It was also made smaller than the average Ag content on the protective film side.
基体上に形成された光記録薄膜と、該光記録薄膜上に
形成された保護膜とからなる光情報記録媒体において
は、保護膜の厚みは基体の厚みに比べて1/100〜1/10程
度であるため、該光記録薄膜の高温高湿環境下における
酸化腐食は保護膜側から始まり次第に基体側へと広が
る。したがって本発明のように光記録薄膜中のAg含有量
を基体側では平均Ag含有量より小さくし保護膜側では平
均Ag含有量よりも大きくすることにより、保護膜側より
進行する光記録薄膜の酸化腐食を強力に防止することが
できる。また、一般に情報の記録再生は光ビームを基体
側から入射させて行うので、光情報記録媒体の記録再生
特性は光記録薄膜の基体側の性質により強く依存する。
従って本発明のように光記録薄膜の基体側でAg含有量が
平均Ag含有量よりも小さくなっていると、基体側におい
ては雑音成分となる析出Ag量が少なく、この結果記録再
生特性も良好に保つことができる。In an optical information recording medium comprising an optical recording thin film formed on a substrate and a protective film formed on the optical recording thin film, the thickness of the protective film is 1/100 to 1/10 of the thickness of the substrate. Therefore, the oxidative corrosion of the optical recording thin film in a high-temperature and high-humidity environment starts from the protective film side and gradually spreads to the substrate side. Therefore, as in the present invention, the Ag content in the optical recording thin film is smaller than the average Ag content on the substrate side and larger than the average Ag content on the protective film side, so that the optical recording thin film traveling from the protective film side Oxidative corrosion can be strongly prevented. In general, information recording and reproduction are performed by irradiating a light beam from the substrate side, so that the recording and reproduction characteristics of the optical information recording medium strongly depend on the properties of the optical recording thin film on the substrate side.
Therefore, when the Ag content on the substrate side of the optical recording thin film is smaller than the average Ag content as in the present invention, the amount of precipitated Ag that is a noise component on the substrate side is small, and as a result, the recording / reproducing characteristics are good. Can be kept.
第１図は、本発明による光情報記録媒体の一実施例を
示したものである。即ち、11はポリカーボネート基板で
あり、その上に光記録薄膜としてAgが添加されたGeTe薄
膜12を有している。更に、該光記録薄膜上に傷や埃を防
止するための樹脂保護膜13を積層した。FIG. 1 shows an embodiment of the optical information recording medium according to the present invention. That is, 11 is a polycarbonate substrate, and has a GeTe thin film 12 to which Ag is added as an optical recording thin film thereon. Further, a resin protective film 13 for preventing scratches and dust was laminated on the optical recording thin film.
ここで基板11はポリカーボネートに限ることなく、従
来から公知のPMMA,ポリオレフィン，エポキシ等の透明
樹脂板，ガラス板を使用できる。Here, the substrate 11 is not limited to polycarbonate, and a conventionally known transparent resin plate such as PMMA, polyolefin, epoxy or the like, or a glass plate can be used.
光記録薄膜12はスパッタリグ法および蒸着法にて作製
する。Ag添加GeTe薄膜において、Ag含有量を基体側では
平均Ag含有量よりも小さくし、保護膜側では平均Ag含有
量よりも大きくする方法を以下に述べる。The optical recording thin film 12 is produced by a sputter rig method and a vapor deposition method. A method for making the Ag content of the Ag-added GeTe thin film smaller than the average Ag content on the substrate side and larger than the average Ag content on the protective film side will be described below.
第２図は、該光記録薄膜を作製する時に使用するスパ
ッタリグ装置の概略図である。真空槽21内の上部に設け
られた回転式基板支持テーブル22の下面に、ポリカーボ
ネート基板11をとりつけ、真空槽21内を約５×10-4Paに
排気後、真空槽21内にAr等の活性ガスを導入してガス圧
を５×10-1Paにする。この状態でGeTeのターゲット23と
Agターゲット24に同時に高周波電力を印加すると、スパ
ッタリグ作用によって基板11上にAgが添加されたGeTe薄
膜が形成される。このとき、第３図に示すようにGeTeの
ターゲット23に印加される高周波電力を一定とし、Agタ
ーゲット24に印加される電力をスパッタリグ開始当初は
小さくし、終了近くにおいて大きくすると、Agが添加さ
れたGeTe薄膜においては、Ag含有量は基板側では平均Ag
含有量よりも小さく、保護膜側では平均Ag含有量よりも
大きくなる。FIG. 2 is a schematic diagram of a sputter rig used for producing the optical recording thin film. The polycarbonate substrate 11 is mounted on the lower surface of the rotary substrate support table 22 provided at the upper part in the vacuum chamber 21. After evacuation of the vacuum chamber 21 to about 5 × 10 −4 Pa, The gas pressure is adjusted to 5 × 10 -1 Pa by introducing an active gas. In this state, GeTe target 23
When high-frequency power is applied to the Ag target 24 at the same time, a GeTe thin film to which Ag is added is formed on the substrate 11 by the sputtering effect. At this time, as shown in FIG. 3, the high-frequency power applied to the GeTe target 23 is kept constant, and the power applied to the Ag target 24 is reduced at the beginning of the sputter rig and increased near the end of the sputtering. In the GeTe thin film, the Ag content is the average Ag on the substrate side.
It is smaller than the content, and is larger than the average Ag content on the protective film side.
真空蒸着法においても同様に、GeTeとAgの２種の蒸発
源からの同時蒸着で、GeTeの蒸発速度を一定とし、Agの
蒸発速度を蒸着開始当初は小さくし終了近くになって大
きくすると、Ag含有量は基体側では平均Ag含有量よりも
小さく、保護膜側では平均Ag含有量よりも大きくなる。Similarly, in the vacuum deposition method, by simultaneously depositing GeTe and Ag from two kinds of evaporation sources, keeping the evaporation rate of GeTe constant, and decreasing the evaporation rate of Ag at the beginning of the deposition start and increasing it near the end of the deposition, The Ag content is smaller than the average Ag content on the substrate side, and larger than the average Ag content on the protective film side.
樹脂保護膜13は、紫外線硬化型樹脂液をスピンナにて
塗布し、その後紫外線を照射すると樹脂は硬化し皮膜を
形成する。樹脂保護膜13は紫外線硬化型樹脂のみならず
湿気硬化型樹脂，二液反応型樹脂，溶剤型樹脂いずれも
適用できる。The resin protective film 13 is formed by applying an ultraviolet-curable resin liquid with a spinner and then irradiating the resin with ultraviolet light to cure the resin and form a film. As the resin protective film 13, not only an ultraviolet curable resin but also a moisture curable resin, a two-component reactive resin, or a solvent resin can be used.
Ag添加GeTe光記録薄膜作製時に、Agターゲットに印加
する電力を一定として作製した比較用の光情報記録媒体
と、Agターゲットに印加する電力をスパッタリグ中に第
３図に示したように変化させた、本発明の一実施例によ
る光情報記録媒体の、光情報記録媒体寿命，再生信号の
信号対雑音比CNRを第１表に比較して示す。During the preparation of the Ag-doped GeTe optical recording thin film, the power applied to the Ag target was kept constant while the power applied to the Ag target was varied as shown in FIG. 3 during the sputtering rig. Table 1 shows the life of the optical information recording medium and the signal-to-noise ratio CNR of the reproduced signal of the optical information recording medium according to one embodiment of the present invention in comparison with Table 1.
ここで媒体寿命は、ディスク状光情報記録媒体にレー
ザ光を照射して、回転数1800rpm,周波数1MHzの信号を記
録し、JISc5024M−１の温湿度加速試験を行い、ビット
誤り率が該試験前の３倍になるまでの試験時間から推量
して求めた。 Here, the medium life was measured by irradiating a disk-shaped optical information recording medium with laser light, recording a signal at a rotation speed of 1800 rpm and a frequency of 1 MHz, performing a temperature / humidity acceleration test of JISc5024M-1, and measuring the bit error rate before the test. It was inferred from the test time until it became three times the value.
第１表に示されるように、上記実施例によると光情報
記録媒体は光記録薄膜内において、Ag含有量が基体側で
は平均Ag含有量よりも小さく、保護膜側において平均Ag
含有量よりも大きくなっているので、媒体寿命が長くし
かも再生信号CNRは良い値を保っている。As shown in Table 1, according to the above embodiment, in the optical information recording medium, the Ag content in the optical recording thin film was smaller than the average Ag content on the substrate side, and the average Ag content on the protective film side.
Since the content is larger than the content, the medium life is long and the reproduction signal CNR keeps a good value.
本発明によれば、光記録薄膜内においてAg含有量が保
護膜側において平均Ag含有量よりも大きくなっているの
で、保護膜側から開始する該光記録薄膜の酸化腐食が防
止され、高温高湿環境下に放置されても長時間正確に情
報を記録再生することのできる光情報記録媒体が得られ
る。また、光記録薄膜の基体側では、Ag含有量は平均Ag
含有量よりも小さくなっているので、Ag添加による記録
再生特性の劣化が小さく、記録再生特性のよい光情報記
録媒体が得られる。According to the present invention, since the Ag content in the optical recording thin film is larger than the average Ag content on the protective film side, oxidative corrosion of the optical recording thin film starting from the protective film side is prevented, An optical information recording medium capable of accurately recording and reproducing information for a long time even when left in a wet environment is obtained. Also, on the substrate side of the optical recording thin film, the Ag content is an average Ag.
Since it is smaller than the content, deterioration of the recording / reproducing characteristics due to the addition of Ag is small, and an optical information recording medium having good recording / reproducing characteristics can be obtained.
第一図は本発明による光情報記録媒体の一実施例を示す
断面図、第２図は本発明に適用しうるスパッタリグ装置
の概略図、第３図はその動作説明に供する線図である。 11……基板 12……光記録薄膜 13……樹脂保護膜 21……真空槽 22……基板支持テーブル 23……GeTeターゲット 24……AgターゲットFIG. 1 is a cross-sectional view showing an embodiment of an optical information recording medium according to the present invention, FIG. 2 is a schematic diagram of a sputter rig applicable to the present invention, and FIG. 3 is a diagram for explaining the operation thereof. 11 ... substrate 12 ... optical recording thin film 13 ... resin protective film 21 ... vacuum chamber 22 ... substrate support table 23 ... GeTe target 24 ... Ag target
Claims (1)
録薄膜上に形成された保護膜からなる光情報媒体におい
て、前記光記録薄膜の主成分をAgが添加されたGeTeと
し、前記光記録薄膜中のAg含有量を基体側では平均Ag含
有量よりも小さくしたことを特徴とする光情報記録媒
体。An optical information medium comprising an optical recording thin film formed on a substrate and a protective film formed on the optical recording thin film, wherein the main component of the optical recording thin film is GeTe to which Ag is added, An optical information recording medium, wherein the Ag content in the optical recording thin film is smaller than the average Ag content on the substrate side.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62326884A JP2571556B2 (en) | 1987-12-25 | 1987-12-25 | Optical information recording medium |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62326884A JP2571556B2 (en) | 1987-12-25 | 1987-12-25 | Optical information recording medium |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH01169747A JPH01169747A (en) | 1989-07-05 |
| JP2571556B2 true JP2571556B2 (en) | 1997-01-16 |
Family
ID=18192821
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP62326884A Expired - Fee Related JP2571556B2 (en) | 1987-12-25 | 1987-12-25 | Optical information recording medium |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2571556B2 (en) |
-
1987
- 1987-12-25 JP JP62326884A patent/JP2571556B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH01169747A (en) | 1989-07-05 |
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