【特許請求の範囲】
【請求項１】基板上に少なくとも記録層が成膜された情報記録媒体であって、前記記録層は、光ビームの照射によって結晶状態と非晶質状態との間で可逆的相変態を生起する相変態層と、前記相変態層の結晶化能を向上させる結晶化能向上層なる層を含み、前記相変態層を成膜する前に前記結晶化能向上層を成膜し、前記相変態層が成膜中に結晶核生成および結晶成長を生起し、前記相変態層の少なくとも一部が成膜後に結晶相に形成され、結晶化能向上層が、テルル化物及びハロゲン化物から選ばれる少なくとも一つの材料からなり、前記テルル化物が、ＳｎＴｅ、ＧｅＴｅ−Ｓｂ 2 Ｔｅ 3 共融組成(以下、ＧｅＳｂＴｅ共融とする)、およびＧｅＴｅ−Ｂｉ 2 Ｔｅ 3 共融組成(以下ＧｅＢｉＴｅ共融とする)から選ばれる少なくとも一つであることを特徴とする情報記録媒体。
【請求項２】前記結晶化能向上層を成膜した場合の前記相変態層を結晶化させるためのエネルギーをＡ、前記結晶化能向上層を成膜しない場合の前記相変態層を結晶化させるためのエネルギーをＢとしたとき、Ａ＜Ｂである請求項１に記載の情報記録媒体。
【請求項３】 前記ハロゲン化物がＺｎＦ2、ＡｌＦ3,ＫＦ,ＣａＦ2,ＮａＦ,ＢａＦ2,ＭｇＦ2,ＬａＦ3,ＬｉＦから選ばれる少なくとも一つである請求項１に記載の情報記録媒体。
【請求項４】 前記相変態層の結晶構造が岩塩型である請求項１または２に記載の情報記録媒体。
【請求項５】 前記相変態層がＧｅＳｂＴｅを含む請求項１，２または４に記載の情報記録媒体。
【請求項６】 前記結晶化能向上層の結晶構造が岩塩型である請求項１または２に記載の情報記録媒体。
【請求項７】 前記テルル化物から選ばれた前記結晶化能向上層の厚みdt(nm)が、1≦dt≦10である請求項１〜３のいずれかに記載の情報記録媒体。
【請求項８】 前記ハロゲン化物から選ばれた前記結晶化能向上層の厚みｄｆ（ｎｍ）が、１≦ｄｆ≦２０である請求項１〜３のいずれかに記載の情報記録媒体。
【請求項９】 前記記録層の初期化を必要としない請求項１〜８のいずれかに記載の情報記録媒体。
【請求項１０】 前記基板が第一の基板と第二の基板の２つの基板からなり、前記２つの基板に前記記録層が形成されており、前記２つの基板を外側にして貼り合わせた二層情報記録媒体である請求項１〜９のいずれかに記載の情報記録媒体。
【請求項１１】 前記基板が第一の基板と第二の基板の２つの基板からなり、前記第一の基板側に前記記録層が形成されており、前記２つの基板を外側にして貼り合わせた二層情報記録媒体である請求項１〜９のいずれかに記載の情報記録媒体。
【請求項１２】請求項１〜１１のいずれかの情報記録媒体の製造方法であって、前記結晶化能向上層を成膜し、その後前記相変態層を成膜するに際し、前記相変態層の成膜中に、前記相変態層を結晶化させることを特徴とする情報記録媒体の製造方法。
【請求項１３】基板上に少なくとも記録層を備える情報記録媒体であって、前記記録層は、光ビームの照射によって結晶状態と非晶質状態との間で可逆的相変態を生起する相変態層と、前記相変態層に積層され前記相変態層の結晶化を促進する結晶核供給層とを含み、前記相変態層が、成膜後に非晶質の状態であり、前記結晶核供給層の非晶質から結晶相への転移温度(以下、結晶化温度という)Ｔx1(℃)と、前記相変態層の結晶化温度Ｔx2(℃)とが、Ｔx2＞Ｔx1の関係を満たすことを特徴とする情報記録媒体。
【請求項１４】 前記相変態層及び前記結晶核供給層は、島状に形成されている請求項１３に記載の情報記録媒体。
【請求項１５】 前記結晶核供給層と前記相変態層とが、前記基板側からこの順序で積層されている請求項１３または１４のいずれかに記載の情報記録媒体。
【請求項１６】 前記相変態層の結晶化を促進する第２の結晶核供給層をさらに含み、前記相変態層と前記第２の結晶核供給層とが前記基板側からこの順序で積層されている請求項１３〜１５のいずれかに記載の情報記録媒体。
【請求項１７】 前記相変態層と前記結晶核供給層とが、前記基板側からこの順序で積層されている請求項１３〜１６のいずれかに記載の情報記録媒体。
【請求項１８】 前記結晶核供給層の融点Ｔm1(℃)と、前記相変態層の融点Ｔm2(℃)とが、Ｔm1＞Ｔm2の関係を満たす請求項１３〜１７のいずれかに記載の情報記録媒体。
【請求項１９】 前記結晶核供給層がＴｅを含む化合物である請求項１３〜１８のいずれかに記載の情報記録媒体。
【請求項２０】 前記結晶核供給層が、ＳｎＴｅおよびＰｂＴｅから選ばれる少なくとも一つを含む請求項１９に記載の情報記録媒体。
【請求項２１】 前記結晶核供給層が、ＳｎＴｅ−Ｍ(ただし、ＭはN,Ag,Cu,Co,Ge,Mn,Nb,Ni,Pd,Pt,Sb,Se,Ti,V,ZrおよびPbTeから選ばれる少なくとも一つの元素または化合物)を含む請求項１９に記載の情報記録媒体。
【請求項２２】 前記Ｍの含有量が０．５〜５０atom%の範囲である請求項２１に記載の情報記録媒体。
【請求項２３】 前記相変態層が、カルコゲン系材料からなる請求項１３〜２２のいずれかに記載の情報記録媒体。
【請求項２４】 前記相変態層が、GeTe,GeSbTe,TeSnSe,InSbTe,GeBiTeおよびAgInSbTeから選ばれる少なくとも一つを含む請求項２３に記載の情報記録媒体。
【請求項２５】前記相変態層が、GeSbTeと、Ag,Sn,Cr,Mn,Pb,Bi,Pd,Se,In,Ti,Zr,Au,Pt,AlおよびNから選ばれる少なくとも一つの元素とを含む請求項２４に記載の情報記録媒体。
【請求項２６】 前記結晶核供給層の厚みd1(nm)と、前記相変態層の厚みd2(nm)とが、d2＞d1の関係を満たす請求項１３〜２５のいずれかに記載の情報記録媒体。
【請求項２７】前記結晶核供給層の厚みd1(nm)が、0.3＜d1≦5の関係を満たす請求項１３〜２６のいずれかに記載の情報記録媒体。
【請求項２８】前記相変態層の厚みd2(nm)が、3≦d2≦20の関係を満たす請求項１３〜２７のいずれかに記載の情報記録媒体。
【請求項２９】前記相変態層が結晶相である場合の情報記録媒体の反射率Rc(%)と、前記相変態層が非晶質である場合の情報記録媒体の反射率Ra(%)とが、Ra＞Rcの関係を満たす請求項１３〜２８のいずれかに記載の情報記録媒体。
【請求項３０】請求項１３〜２９のいずれかの情報記録媒体の製造方法であって、記録層を成膜する工程は、気相薄膜堆積法を用いて、まず相変態層を成膜する工程を実施し、次に結晶核供給層を成膜する工程を実施し、前記相変態層が非晶質となることを特徴とする情報記録媒体の製造方法。
【請求項３１】請求項１３〜２９のいずれかの情報記録媒体の記録再生方法であって、記録層は、相変態層と、結晶核供給層とを含み、前記記録層にレーザビームを照射することによって、前記相変態層が、初期化することなく非晶質の状態で情報の記録が開始されることを特徴とする情報記録媒体の記録再生方法。
[Claims]
1. An information recording medium having at least a recording layer formed on a substrate, wherein said recording layer causes a reversible phase transformation between a crystalline state and an amorphous state by irradiation with a light beam. A phase transformation layer, and a layer that serves as a crystallization ability improving layer that improves the crystallization ability of the phase transformation layer, wherein the crystallization ability improving layer is formed before the phase transformation layer is formed, The transformation layer causes crystal nucleation and crystal growth during film formation, and at least a part of the phase transformation layer is formed in a crystal phase after film formation,The crystallization-enhancing layer is made of at least one material selected from a telluride and a halide, and the telluride is made of SnTe, GeTe-Sb. Two Te Three Eutectic composition (hereinafter referred to as GeSbTe eutectic) and GeTe-Bi Two Te Three At least one selected from eutectic compositions (hereinafter referred to as GeBiTe eutectic)An information recording medium characterized by the above-mentioned.
2. The energy for crystallizing the phase change layer when the crystallization ability improving layer is formed is A, and the phase change layer when the crystallization ability improvement layer is not formed is crystallized. 2. The information recording medium according to claim 1, wherein A <B, where B is the energy to be applied.
(3) SaidThe halide is ZnFTwo, AlFThree, KF, CaFTwo, NaF, BaFTwo, MgFTwo, LaFThreeAnd at least one selected from LiF.1An information recording medium according to claim 1.
(4) Said3. The information recording medium according to claim 1, wherein the crystal structure of the phase transformation layer is a rock salt type.
(5) SaidThe phase transformation layer comprises GeSbTe, Claim 1 or 2, or4An information recording medium according to claim 1.
6. SaidThe crystal structure of the crystallinity improving layer is a rock salt type.1 or 2An information recording medium according to claim 1.
7. SaidSelected from tellurideSaidThe thickness dt (nm) of the crystallization ability improving layer, 1 ≦ dt ≦ 10,One of 1-3An information recording medium according to claim 1.
Claim 8. SaidSelected from halidesSaidThe thickness df (nm) of the crystallinity improving layer is 1 ≦ df ≦ 20.One of 1-3Information recording medium as described.
9. SaidClaim 1 which does not require initialization of the recording layer.8An information recording medium according to any one of the above.
10. SaidThe substrate is the first substrate and the second substrateTwo boardsConsisting ofThe two substratesToSaidA two-layer information recording medium in which a recording layer is formed and the two substrates are bonded together with the two substrates facing outward.9An information recording medium according to any one of the above.
11. The substrate comprises two substrates, a first substrate and a second substrate,On the first substrate sideSaidA recording layer is formed,A two-layer information recording medium in which the two substrates are bonded together with the two substrates facing outward.Claim1-9An information recording medium according to any one of the above.
12. The method according to claim 1,11The method for manufacturing an information recording medium according to any one of the above,SaidAfter forming a crystallization-enhancing layer,SaidWhen forming the phase transformation layer,Crystallizing the phase transformation layer during the formation of the phase transformation layerA method for manufacturing an information recording medium, comprising:
13. An information recording medium comprising at least a recording layer on a substrate, wherein said recording layer undergoes a reversible phase transformation between a crystalline state and an amorphous state by irradiation with a light beam. A crystal nucleus supply layer laminated on the phase transformation layer and promoting crystallization of the phase transformation layer.Only, the phase change layer is in an amorphous state after film formation, and the transition temperature from the amorphous state to the crystalline phase of the crystal nucleus supply layer (hereinafter, referred to as crystallization temperature) Tx1 (° C.), The crystallization temperature Tx2 (° C.) of the phase transformation layer satisfies the relationship of Tx2> Tx1An information recording medium characterized by the above-mentioned.
14. SaidPhase transformation layer andSaidThe crystal nucleus supply layer is formed in an island shape.13An information recording medium according to claim 1.
15. SaidCrystal nucleus supply layer andSaidThe phase transformation layer isSaidClaims that are laminated in this order from the substrate side13 or 14An information recording medium according to any one of the above.
16. SaidThe phase change layer further includes a second crystal nucleus supply layer that promotes crystallization of the phase change layer, wherein the phase change layer and the second crystal nucleus supply layer are connected to each other.SaidClaims that are laminated in this order from the substrate side13-15An information recording medium according to any one of the above.
17. SaidWith the phase transformation layerSaidThe crystal nucleus supply layer isSaidClaims that are laminated in this order from the substrate side13-16An information recording medium according to any one of the above.
18. SaidMelting point Tm1 (° C.) of the crystal nucleus supply layer;SaidThe melting point Tm2 (° C.) of the phase transformation layer satisfies the relationship of Tm1> Tm2.13-17An information recording medium according to any one of the above.
(19) SaidThe crystal nucleus supply layer is a compound containing Te.13-18An information recording medium according to any one of the above.
20. SaidThe crystal nucleus supply layer includes at least one selected from SnTe and PbTe.19An information recording medium according to claim 1.
21. SaidThe crystal nucleus supply layer is made of SnTe-M (where M is at least one selected from N, Ag, Cu, Co, Ge, Mn, Nb, Ni, Pd, Pt, Sb, Se, Ti, V, Zr and PbTe). Claims containing two elements or compounds)19An information recording medium according to claim 1.
22. SaidThe content of M is in the range of 0.5 to 50 atom%.21An information recording medium according to claim 1.
23. SaidThe claim wherein the phase transformation layer is made of a chalcogen-based material.13-22An information recording medium according to any one of the above.
24. SaidThe phase transformation layer contains at least one selected from GeTe, GeSbTe, TeSnSe, InSbTe, GeBiTe and AgInSbTe.23An information recording medium according to claim 1.
25. The phase transformation layer according to claim 1, wherein the phase transformation layer is GeSbTe and at least one element selected from Ag, Sn, Cr, Mn, Pb, Bi, Pd, Se, In, Ti, Zr, Au, Pt, Al and N. Claims including24An information recording medium according to claim 1.
26. SaidThe thickness d1 (nm) of the crystal nucleus supply layer and the thickness d2 (nm) of the phase transformation layer satisfy a relationship of d2> d1.13-25An information recording medium according to any one of the above.
27. The thickness d1 (nm) of the crystal nucleus supply layer satisfies the relationship of 0.3 <d1 ≦ 5.13-26An information recording medium according to any one of the above.
28. The thickness d2 (nm) of the phase transformation layer satisfies the relationship of 3 ≦ d2 ≦ 20.13-27An information recording medium according to any one of the above.
29. A reflectance Rc (%) of the information recording medium when the phase change layer is a crystalline phase, and a reflectance Ra (%) of the information storage medium when the phase change layer is amorphous. Satisfy the relationship of Ra> Rc13-28An information recording medium according to any one of the above.
30. Claim13-29Wherein the recording layer is formed as a film.The process isFirst, a phase transformation layer is formed using a vapor phase thin film deposition methodImplement the process ofNext, a crystal nucleus supply layer is formed.The phase transformation layer becomes amorphousA method for manufacturing an information recording medium, comprising:
31. Claim13-29The recording / reproducing method of any one of the information recording media, wherein the recording layer includes a phase transformation layer and a crystal nucleus supply layer, by irradiating the recording layer with a laser beam,Recording of information is started in an amorphous state without initializing the phase transformation layer.A recording / reproducing method for an information recording medium, characterized by comprising: