JPS61152487A - Photo-information recording medium - Google Patents

Abstract

PURPOSE:To prevent the cracking of the recorded portion of GeTe-thin film by phase dislocation by adding substances of 31 or more atomic numbers among the III, IV, and V groups' elements to GeTe in the thin film. CONSTITUTION:On a base plate 2, e.g., glass plate, polyvinyl chloride resin, polycarbonate resin, etc., GeTe and Sb for example (80-99% GeTe and 20-1% Sb) are deposited by vapor deposition or sputtering to form a recording film 1 of GeTeSbx. For regeneration of recording, lasers 3 is irradiated from the base plate 2 side, where the reflectivity of the portion exposed to lasers is increased by the heat of the lasers. Since the reflectivity of the thin film is lowered between thicknesses of 800Angstrom -1,200Angstrom , largest contract can be obtained within the range. Cracking of the recording portion by phase dislocation can be prevented, and recording of high C/N can be obtained.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an optical information storage system in which a recording film for recording information is attached to a substrate by changing optical characteristics by thermal transformation due to thermal energy of a laser source. Regarding recording media, 4゜ [Conventional technology] Ith! The applicant proposed a GeTe Wt film as an "optical information recording medium" in Japanese Patent Application No. 59-13745. This is recorded by changing the optical characteristics through thermal transformation.Record 11
It has excellent properties such as 4th grade, and a large contrast can be obtained with a single layer film.

[Ishima's point that invention attempts to solve]

However, the recorded portion has disadvantages such as L volume shrinkage due to crystal phase transition and shrinkage due to difference in thermal expansion coefficient between the substrate and the recording film.

[Purpose of the invention]

The present invention is aimed at preventing two tubes due to the recorded crystalline phase transition of a GeTe thin film. Therefore, non-invention is due to GeTe.
A recording thin film made by adding all substances of the V group with an atomic number of 31 or more.
A description of the T-doped thin film.

FIG. 1 shows an embodiment of the invention, in which a glass plate is used as the substrate 2;
Using polymethyl methacrylate resin, polyvinyl chloride skin fat, polycarbonate resin, etc., GeTe and Sb (GeTe: 80-99'4, Sb: 20
A recording film 1'f: is formed on GeTe5bz by depositing sb by vacuum evaporation, sputtering, or sputtering. sb Yu Tea
(GeTe: 70-99%, S
(b, xTe+v: 30 to 1 inch) may be deposited in two ways by vacuum evaporation and sputtering.

To perform recording and playback on the original information recording medium created in this way,
As shown in Fig. 1, recording is performed by irradiating a laser 3t-4o from a substrate 2g4, and in this case, recording is performed by irradiating a strong laser beam 2. Sue. The signal can be read based on the difference in reflectance. Since the reflectance of a thin film of this material is low between 800'A and 1200'A2, the greatest contrast and last can be obtained in this range of film thickness.4°Figure 2 shows Gen5Te*
aSba f was deposited on a glass substrate with a film thickness of 1000°A, and the dependence of the base side anti-1\I ratio and transmittance on the heat treatment temperature at the original wavelength of 830 nm is shown. The heat treatment time was about 10 minutes, and the figure shows that the reflectance changes from 17% to 49 degrees after heat treatment. In addition, the reflectance and transmittance of the thin film before heat treatment are 17% and 8%, respectively, and the absorption rate is about 75%, and since it is a Te compound and has a relatively low thermal conductivity, The heat absorption of semiconductor laser light is done efficiently. In addition, the reflectance change temperature of the GeTe thin film is between 160°C and 160°C.
Since the temperature is lower than that of grass compared to 70°C, the recording sensitivity is not high. Next, as a result of recording and reproducing experiments, the recording sensitivity was higher than that of the GeTe thin film, and the disc surface laser power was 7.5 at a linear velocity of 2 m/see.
There were no cracks in the pits up to mw 250 KHz (a C/#4 level of 50 dB or more was obtained).

Not limited to the above implementation sequence, one of Bi and In may be completely added to GeT, or BitTe*XI may be added to GeTe.
Similar results were obtained when one of nTe was mixed and made into a thin film. Also, among the mrvv group, the atomic number is 31
All of the above substances have low thermal conductivity ← 6', low melting point, and are easy to form into thin films (and are easy to mix with GeTe, etc.), so good results can be obtained by depositing them together with GeTe in the same manner as above. was gotten.

As described above, the z-source information recording medium according to the present invention is a Getlb
Since a recording thin film is obtained by doping a substance with an atomic number of 31 or more from the TIIIVV group, it is possible to prevent cracks due to crystal phase change in the recorded area, and it is possible to record with a high C/N and to have a stone effect. 40

[Brief explanation of the drawing]

FIG. 1 shows an embodiment of a recording medium according to the invention.
The r-plane view, FIG. 2, illustrates the characteristics of the recording medium according to the present invention. 1...Substrate 2...Recording film 3...Laser L-9″L 10th 1st day

Claims (1)

[Claims] In an optical information recording medium in which a thin film is formed on a substrate and information is recorded by forming a portion with changing optical characteristics in the thin film using energy such as light or heat, the main component of the thin film is GeT.
Add 1 substance with an atomic number of 31 or higher from group IIIIVV to e.
% or more and 20% or less.