Information recording medium and method for producing the same

• US 20030138669A1
• Filed: 12/06/2002
• Published: 07/24/2003
• Est. Priority Date: 12/07/2001
• Status: Active Grant

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Yamada, Noboru, Kojima, Rie, Habuta, Haruhiko
• Granted Patent: US 6,761,950 B2
• Time in Patent Office: Days
• US Class Current: 428/694ST
• CPC Class Codes: G11B 2007/24308 transition metal elements of group 11 (Cu, Ag, Au)
• CPC Class Codes: G11B 2007/2431 group 13 elements (B, Al, Ga, In)
• CPC Class Codes: G11B 2007/24312 group 14 elements (e.g. Si, Ge, Sn)
• CPC Class Codes: G11B 2007/24314 group 15 elements (e.g. Sb, Bi)
• CPC Class Codes: G11B 2007/24316 group 16 elements (i.e. chalcogenides, Se, Te)
• CPC Class Codes: G11B 2007/2432 Oxygen
• CPC Class Codes: G11B 2007/25706 containing transition metal elements (Zn, Fe, Co, Ni, Pt)
• CPC Class Codes: G11B 2007/25708 containing group 13 elements (B, Al, Ga)
• CPC Class Codes: G11B 2007/2571 containing group 14 elements except carbon (Si, Ge, Sn, Pb)
• CPC Class Codes: G11B 2007/25711 containing carbon
• CPC Class Codes: G11B 2007/25713 containing nitrogen
• CPC Class Codes: G11B 2007/25715 containing oxygen
• CPC Class Codes: G11B 2007/25716 containing sulfur
• CPC Class Codes: G11B 2007/25718 containing halides (F, Cl, Br, l)
• CPC Class Codes: G11B 7/00454 involving phase-change effects
• CPC Class Codes: G11B 7/2403 Layers; Shape, structure or physical properties thereof
• CPC Class Codes: G11B 7/24038 Multiple laminated recording layers
• CPC Class Codes: G11B 7/252 of layers other than recording layers
• CPC Class Codes: G11B 7/256 of layers improving adhesion between layers
• CPC Class Codes: G11B 7/2578 consisting essentially of inorganic materials
• CPC Class Codes: G11B 7/259 : based on silver
• CPC Class Codes: H10N 70/026 : by physical vapor deposition, e.g. sputtering
• CPC Class Codes: H10N 70/231 : based on solid-state phase change, e.g. between amorphous and crystalline phases, Ovshinsky effect
• CPC Class Codes: H10N 70/826 : adapted for essentially vertical current flow, e.g. sandwich or pillar type devices
• CPC Class Codes: H10N 70/8616 : Thermal insulation means
• CPC Class Codes: H10N 70/8828 : Tellurides, e.g. GeSbTe
• CPC Class Codes: Y10T 428/21 : Circular sheet or circular blank

Abstract

An information recording medium which ensures high reliability and favorable overwrite cyclability is provided, even when an interface layer is not provided between a recording layer and a dielectric layer. The recording layer 4 and the dielectric layers 2 and 6 are formed on the surface of the substrate 1. In the recording layer 4, a phase change is generated between a crystal phase and an amorphous phase by irradiation of light or application of an electric energy. The dielectric layers 2 and 6 are Zr—Zn—S—O-based material layers comprising Zr, Zn, S and O, preferably consisting essentially of a material expressed, for example, with the formula (ZrO₂)_X(Zn—S)_100−X (mol %) wherein X is in the range of 50≦X≦80.

Claims

1. An information recording medium comprising:

a substrate;

a recording layer wherein a phase change between a crystal phase and an amorphous phase is generated by irradiation of light or application of an electric energy; and

a Zr—

Zn—

S—

O-based material layer comprising Zr, Zn, S and O.

2. The information recording medium according to claim 1, wherein the Zr—

Zn—

S—

O-based material layer consists essentially of a material expressed with the formula (1);

Zr_BZn_CS_DO<sub>100−

B−

C−

D (atomic %)</sub> 

 

(1)

wherein B, C and D are respectively within the range of 8≦

B≦

33, and 3≦

C≦

30, C≦

D≦

2C<

45, and satisfy 40≦

B+C+D≦

80.

3. The information recording medium according to claim 1, wherein the Zr—

Zn—

S—

O-based material layer further contains Si and consists essentially of a material expressed with the formula (2);

Zr_ESi_FZn_GS_HO<sub>100−

E−

F−

G−

H</sub> (atomic %) 

 

(2)

wherein E, F, G and H are respectively in the range of 1≦

E≦

30, 0<

F≦

23, 2≦

G≦

30 and G≦

H≦

2G<

45, and satisfy 40≦

E+F+G+H≦

80.

4. The information recording medium according to claim 2, wherein the Zr—

Zn—

S—

O-based material layer consists essentially of a material expressed with the formula (11);

(ZrO₂)_X(Zn—

S)<sub>100−

X</sub> (mol %) 

 

(11)

wherein X is in the range of 50≦

X≦

80.

5. The information recording medium according to claim 3, wherein the Zr—

Zn—

S—

O-based material containing Si consists essentially of a material expressed with the formula (21);

(ZrO₂)_Y(SiO₂)_Z(Zn—

S)<sub>100−

Y−

Z</sub> (mol %) 

 

(21)

wherein Y and Z are respectively within the range of 20≦

Y≦

70, and 10≦

Z≦

50, and satisfy 50≦

Y+Z≦

80.

6. The information recording medium according to claim 5, wherein the material expressed with the formula (21) contains ZrO₂ and SiO₂ at a substantially equal ratio and is expressed with the formula (22):

(ZrSiO₄)_A(Zn—

S)<sub>100−

A</sub> (mol %) 

 

(22)

wherein A is within the range of 33≦

A≦

67.

7. The information recording medium according to claim 1, wherein the phase change is generated reversibly in the recording layer.

8. The information recording medium according to claim 7, wherein the recording layer comprises a material selected from Ge—

Sb—

Te, Ge—

Sn—

Sb—

Te, Ge—

Bi—

Te, Ge—

Sn—

Bi—

Te, Ge—

Sb—

Bi—

Te, Ge—

Sn—

Sb—

Bi—

Te, Ag—

In—

Sb—

Te and Sb—

Te.

9. The information recording medium according to claim 1, wherein the thickness of the recording layer is 15 nm or less.

10. The information recording medium according to claim 1, wherein two or more recording layers are provided.

11. The information recording medium according to claim 1, wherein a first dielectric layer, the recording layer, a second dielectric layer, and a reflective layer are formed in this order on one surface of the substrate, and at least one of the first dielectric layer and the second dielectric layer is the Zr—

Zn—

S—

O-based material layer which contacts the recording layer.

12. The information recording medium according to claim 1, wherein a reflective layer, a second dielectric layer, the recording layer and a first dielectric layer are formed in this order on one surface of the substrate, and at least one of the first dielectric layer and the second dielectric layer is the Zr—

Zn—

S—

O-based material layer which contacts the recording layer.

13. A method for producing an information recording medium which comprises a substrate, a recording layer, and a Zr—

Zn—

S—

O-based material layer comprising Zr, Zn, S and O, the method comprising a process of forming the Zr—

Zn—

S—

O-based material layer by a sputtering method.

14. The method according to claim 13, wherein a sputtering target consisting essentially of a material expressed with the formula (10):

Zr_bZn_cS_dO<sub>100−

b−

c−

d</sub> (atomic %) 

 

(10)

wherein, b, c, and d are respectively within the range of 11≦

b≦

30, 5≦

c≦

27 and c≦

d≦

2c<

40, and satisfy 40≦

b+c+d≦

80, is used in the process of forming the Zr—

Zn—

S—

O-based material layer by the sputtering method.

15. The method according to claim 13, wherein a sputtering target consisting essentially of a material expressed with the formula (20):

Zr_eSi_fZn_gS_hO<sub>100−

e−

f−

g−

h</sub> (atomic %) 

 

(20)

wherein e, f, g and h are respectively in the range of 3≦

e≦

27, 1<

f≦

20, 5≦

g≦

27 and g≦

h≦

2g<

40, and satisfy 40≦

e+f+g+h≦

80, is used to form a Zr—

Zn—

S—

O-based material layer containing Si in the process of forming the Zr—

Zn—

S—

O-based material layer by the sputtering method.

16. The method according to claim 13, wherein a sputtering target consisting essentially of a material expressed with the formula (110):

(ZrO₂)_x(Zn—

S)<sub>100−

x</sub> (mol %) 

 

(110)

wherein x is in the range of 50≦

x≦

80, is used in the process of forming the Zr—

Zn—

S—

O-based material layer by the sputtering method.

17. The method according to claim 13, wherein a sputtering target consisting essentially of a material expressed with the formula (210):

(ZrO₂)_y(SiO₂)_z(Zn—

S)<sub>100−

y−

z</sub> (mol %) 

 

(210)

wherein y and z are respectively within the range of 20≦

y≦

70, and 10≦

z≦

50, and satisfy 50≦

y+z≦

80, is used to form a Zr—

Zn—

S—

O-based material layer containing Si in the process of forming the Zr—

Zn—

S—

O-based material layer by the sputtering method.

18. The method according to claim 17, wherein the material expressed with the formula (210) contains ZrO₂ and SiO₂ at a substantially equal ratio and is expressed with the formula (220):

(ZrSiO₄)_a(Zn—

S)<sub>100−

a</sub> (mol %) 

 

(220)

wherein a is within the range of 33≦

a≦

67.