WO2005005683A1

WO2005005683A1 - Sputtering target and optical recording medium

Info

Publication number: WO2005005683A1
Application number: PCT/JP2004/005395
Authority: WO
Inventors: Hideyuki Takahashi
Original assignee: Nikko Materials Co., Ltd.
Priority date: 2003-07-15
Filing date: 2004-04-15
Publication date: 2005-01-20
Also published as: JPWO2005005683A1; JP4582457B2; TW200502412A; TWI288180B

Abstract

A Ge(α)-In(β)-Sb(Ϝ)-Te(δ) alloy sputtering target for optical recording media characterized in that letting the sum of the respective composition ratios α, β, Ϝ, δ (atom%) be 100, their ranges are 0.1≤α≤10, 0.1≤β≤10, 60≤Ϝ≤90, 10≤δ<22. An optical recording medium made of the alloy is also disclosed. Few particles are produced during sputtering, and consequently a high-quality thin film is stably formed. The optical recording medium hardly causes an error of record bits and has a high recording density.

Description

Sputtering targets and optical recording media

Technical field

The present invention relates to a sputtering method and a method for manufacturing the same, and an optical recording medium, and in particular, generation of particles during sputtering is small.

Ge-In-Sb-Te alloy sheet that can stably produce high-quality thin films and obtain optical recording media free of recording bit errors

The present invention relates to a sputtering target and an optical recording medium comprising the same alloy.

Background art

In recent years, high-density recording optical disc technology capable of recording and reproducing without the need for a magnetic head has been developed, and interest has rapidly increased. This optical disk is classified into three types: read-only type, write-once type, and rewritable type. The phase change method used in write-once type or rewritable type has attracted special attention.

A phase-change optical disk records and reproduces information by heating a recording thin film on a substrate by irradiating a laser beam and causing a crystallographic phase change (amorphous crystal) in the structure of the recording thin film. More specifically, information is reproduced by detecting a change in reflectance caused by a change in an optical constant between the phases.

The above-mentioned phase change is performed by irradiating a laser beam with a diameter of about 1 to several meters. In this case, for example, when a laser beam of 1 im passes at a linear velocity of 1 OmZs, the time at which a point on the optical disc is irradiated with light is 100 ns, and within this time, the phase It is necessary to detect the change and the reflectance. Further, in order to realize the above-mentioned crystallographic phase change, that is, a phase change between amorphous and crystalline, an optical recording medium suitable for this is required. In general, D VD- phase change optical disk such as a RAM, the number of rewrites is guaranteed 10 ^5-10 ⁶ times.

On the other hand, when a thin film for an optical recording medium is formed on a substrate, sputtering is used. However, depending on the material of the target, the generation of particles increases, and the quality may deteriorate. Particularly, in a high-density recording medium, a recording bit error caused by particles or the like becomes a serious problem. As a result, there is a problem that the yield is reduced due to defective products.

Conventionally, an optical recording medium that has been proposed is a target made of Ge (a) -In (β) -Sb (r) —Te (δ) alloy, and each component composition ratio α + β + Τ + δ (atomic%) = 100, 0.1≤≤≤7, 1≤ι3≤9, 61≤7≤75, 22≤ (3≤30, and CLV and CAV recording are possible. An optical recording medium has been proposed (see JP-A-2002-264155).

Also, when expressed as G e _a X _b S b _y T e ₍₁ _ _a _ _b _ _y) , X is from In, A u, Cu, Al, Ga, P b, T i, S n At least one element selected, within the range of 0.001≤a≤0.20, 0.011≤b≤0.20, 0.40≤y≤0.90 and the recording layer An optical recording medium containing nitrogen has been proposed (see JP-A-2002-264514).

Further, a phase change optical recording layer in which Sb and Te are essential elements and at least one or more types of X elements are added to this SbTe, where X is Ag, Au, Cu, Zn, An optical recording medium which is selected from B, Al, Ga, In, Si, Ge, Sn, Pb, N, P, Bi, La, Ce, Cd, and Tb has been proposed. (See Japanese Patent Application Laid-Open No. 2002-245663). In addition, high purity Ge or A1, Si, Fe, Cr, Ta, Nb, Cu, Mn, Mo, W, Ni, Ti, Zr, Hf, Co, I A Ge alloy containing at least one element selected from r, Pt, Ru, B and C in the range of 0.1 to 50 & 1: atomic%, wherein the Ag and Au contents are respectively A sputtering target for a phase change optical disk having a concentration of 5 ppm or less has been proposed (see Japanese Patent Application Laid-Open No. 2002-69624). Disclosure of the invention

The present invention is directed to an optical recording medium for optical recording media that generates a small amount of particles during sputtering, can stably produce a high-quality thin film, has no recording bit error, and can achieve a high recording density. Provided are an e-In-Sb-Te alloy sputtering target and a method for producing the alloy target, and an optical recording medium comprising the alloy.

In order to solve the above-mentioned problems, the present inventors have conducted intensive studies, and as a result, have achieved high recording density by selecting a Ge—In—Sb—Te alloy having an appropriate composition. It has been found that the generation of particles during sputtering can be effectively suppressed by strictly limiting the oxygen content and strictly adjusting the crystal grain size.

The present invention is based on this finding,

1. G e (a) — In (β) — S b (r) — Te (δ) alloy, with each component composition ratio β, τ, δ (atomic%) The optical recording medium is characterized by being in the range of 0.1 ≤ 1 ≤ 10, 0.1 ≤; 3 ≤ 10, 60 ≤ r ≤ 90, 1 0 ≤ δ <22, where the sum of G e — I η — S b -T e alloy sputtering head and optical recording medium made of the same alloy 2. The Ge—In—Sb—Te alloy sputtering target for an optical recording medium according to 1 above, wherein the oxygen content is not more than 1,500 ppm, and an optical recording medium comprising the alloy.

3. The Ge—In—Sb—Te alloy sputtering ring for optical recording media described in 1 above, characterized by having an oxygen content of 800 pm or less. Optical recording medium

4. The Ge—In—Sb—Te alloy sputtering target for an optical recording medium according to any one of the above 1 to 3, characterized in that the target has an average crystal grain size of 100 m or less.

5. The Ge—In—Sb—Te alloy sputtering target for optical recording media according to any one of the above items 1 to 3, wherein the target has an average crystal grain size of 50 m or less.

6. The Ge-In-Sb-Te alloy sputtering for optical recording media according to any one of the above items 1 to 5, wherein the iron content is 1 to 100 ppm. Evening get

I will provide a. The invention's effect

The Ge—In—Sb—Te alloy sputtering target for the optical recording medium of the present invention and the optical recording medium composed of the same alloy have low particle generation during sputtering and are stable and high in quality. This has an excellent effect that a thin film can be produced and a high recording density can be achieved without occurrence of recording bit error. BEST MODE FOR CARRYING OUT THE INVENTION

The Ge—In—Sb—Te alloy sputtering target for an optical recording medium of the present invention and the optical recording medium comprising the alloy are as follows: G e () -I In (β) —S b (r) − It is composed of T e (δ) alloy, and assuming that the sum of the component composition ratios α, β, γ, and δ (atomic%) is 100, 0.1 ≤ H ≤ 10 and 0.1 ≤ β ≤ 1 0, 6 0 ≤ f ≤ 90, 1 0 ≤ δ <22 This alloy composition is a suitable composition that can achieve a high recording density, realizes a crystallographic phase change, that is, a phase change between amorphous and crystal, and can greatly improve the number of rewrites. Further, the Ge—In—Sb—Te alloy sputtering target for an optical recording medium of the present invention has a strict oxygen content of not more than 1500 ppm, more preferably not more than 800 ppm. Limited. As a result, the generation of particles during sputtering is remarkably reduced, a stable high-quality thin film can be produced, no recording bit error occurs, and a high recording density of an optical recording medium can be achieved. Manufacturing becomes possible.

In addition, oxygen in the optical recording medium is selectively bonded to Ge, so that the stability of mutual transformation between amorphization and crystallization is deteriorated, and the number of times of repeated recording is reduced. Therefore, limiting (reducing as much as possible) the amount of oxygen in the optical recording medium is important for obtaining high quality films.

In order to prevent the generation of particles during sputtering, the average crystal grain size of the target should be 100

The following is also very effective. This makes it possible to produce a good thin film with no recording pit error. In particular, it is desirable that the average crystal grain size of the target is 50; m or less. Further, it is effective to set the iron content in the Ge-In-Sb-Te alloy sputtering target (recording medium) for the optical recording medium to 1 to 100 ppm. . If the addition is less than 1 ppm, the effect of the addition is ineffective, and if it exceeds lOO ppm, the CNR and D〇W deteriorate, so when iron is added, the Fe content should be 1 to 100 p pm is desirable.

The Ge-In-Sb-Te alloy sputtering target for an optical recording medium of the present invention was obtained by synthesizing Ge powder, In powder, Sb powder, and Te powder in an ampoule. After the ingot is ground to a predetermined particle size, uniformly dispersed and mixed, using a hot press, the sintering temperature is 400 to 600 ° C, and the surface pressure is 75 to 250 kg / cm. It can be manufactured by sintering under the conditions of ² . Example

Hereinafter, description will be made based on examples and comparative examples. This embodiment is merely an example, and the present invention is not limited to this embodiment. That is, the present invention is limited only by the claims, and includes various modifications other than the examples included in the present invention.

(Examples 1 to 7)

Prepare Ge powder, In powder, Sb powder, and Te powder with a purity of 5 N (99.99.99%), and use these powders as Ge () — In (β) — S b ( r) — Compounded to give Te (δ), synthesized in an ampoule, crushed the obtained ingot to a predetermined particle size, filled in a carbon die, and heated to a temperature of 600 ° C. Hot pressing was performed under the condition of a pressure of 150 kg / cm ² .

This sintered body was finished to obtain evening get. The relative density of the target was 99% (5.54 g / cm ³ at 100% density). The density of samples arbitrarily collected from the three spots in this evening was measured by the Archimedes method. In the same composition, Te content δ (at%), oxygen content (wtp pm), particle size (am) Fe content, CNR (carrier to noise ratio), DOW (direct over write), Table 1 shows the results of particle generation.

Note that CNR (dB) indicates a measured value at 30 m / s, and DOW indicates an evaluation result by jitter at the time of performing overwrite recording 100 times. Jitter is the value of the re-signal deviation of the minimum pit length signal (3 T) from the maximum pit length signal (11 T). Judged.

The evaluation sample, on D VD blank media §, Z n S- S I_〇 2 (4 5 nm), the recording layer (1 5 nm), Z n S - S i 0 2 (2 0 nm), A It was fabricated by continuous deposition of 1-Ti (150 nm). Comparative example

(Comparative Examples 1-6)

Prepare Ge powder, In powder, Sb powder, and Te powder with a purity of 5 N (99.99.99%), and use these powders as G e () — In (β)-S b ( r) — T e (δ), dry-blended and synthesized in an ampoule. Hot pressing was performed under the conditions of 600 ° C. and a pressure of 150 kg / cm ² . This sintered body was finished to obtain an evening get. The relative density of the evening get was 99% (5. SA gZcm ³ at 100% density). The density of samples arbitrarily collected from the three spots in this evening was measured by the Archimedes method. For the same composition, the Te content δ (at%), oxygen content (wtp pm), particle size (m), Fe content, CNR (d B), DOW, and the results of particle generation during sputtering are shown below. Table 1 shows a comparison with the examples. The CNR (dB) measurement value, DOW measurement value, and sputtering conditions of the evaluation sample were performed in the same manner as in the example. table 1

Particles #K indicate less than 500 particles / wafer, and NG indicates more than 500 particles / wafer. Examples 1 to 6 show that the oxygen content is in the range of 700 to 130 ppm, the particle size is in the range of 30 to 89 m, the CNR (dB) is in the range of 45 to 55, and the DOW However, the amount of generated particles was good.

Note that, in Example 7, the Fe content was <1 wtp pm, but the oxygen content in the raw material was as low as 500 ppm or less (450 wtp pm). In addition, CNR (dB), DOW, and particle generation were all good.

On the other hand, in Comparative Example 1, the amount of oxygen was as large as 2000 ppm, and the amount of DOW and particles generated was poor. In Comparative Example 2, since the particle size was as large as 200 xm, the amount of generated particles was poor. In Comparative Example 3, the DOW deteriorated because the Fe content was too high at 120 ppm. In Comparative Example 4, since the oxygen content was as high as 2500 ppm and Fe <lppm, the DOW and the amount of particles generated were poor. In the absence of Fe, oxygen is high. Comparative Example 5 had a composition deviation of 62.2.Oat% (excessive), and thus had poor DOW. Comparative Example 6 had a composition deviation of <55.0 at% (small), and thus had poor DOW.

As described above, in a target composed of G e («) — In (β)-S b (r)-T e (δ) alloy, the deviation of the T e ((5) It can be seen that the characteristics are greatly affected.

Further, the oxygen content and the particle size of the target have good CNR (dB), DOW and an effect of suppressing generation of particles within the range of the present invention. Further, the Fe content affects the amount of oxygen, and the presence of an appropriate amount of Fe has an effect of suppressing generation of particles during sputtering. It can also be seen that when the oxygen content is sufficiently low, similar good results are obtained regardless of the Fe content. 0 Industrial applicability

The present invention relates to an optical recording medium capable of stably producing a high-quality thin film with little generation of particles during sputtering, generating no recording bit error, and achieving a high recording density. G e — In — S b — Te alloy Applicable to sputtering targets, methods for manufacturing the same alloy targets, and optical recording media made of the same alloys.

Claims

Scope of Claim 1. A target composed of an alloy of Ge ()-In (β) -Sb (r) -Te (δ), wherein the composition ratio of each component is β, r, δ (Atomic%) as 1 0 0, 0.1 ≤ «≤ 1 0, 0.1 ≤ β≤ 1 0, 6 0 ≤ r≤ 9 0, 1 0 ≤ (5 <2 2 An optical recording medium comprising a Ge—In_Sb—Te alloy sputtering target for an optical recording medium, the optical recording medium comprising the alloy.

2. The Ge—In—Sb—Te alloy sputtering ring for an optical recording medium according to claim 1, wherein the oxygen content is not more than 1500 ppm. And an optical recording medium comprising the same alloy.

3. The Ge—In—Sb—Te alloy sparing ring for optical recording media according to claim 1, wherein the oxygen content is 800 ppm or less.

—Get and optical recording media made of the same alloy.

4. The optical recording medium according to any one of claims 1 to 3, wherein the target has an average crystal grain size of 100 / xm or less. Te alloy sputtering target.

5. The Ge—In—Sb—T for optical recording media according to any one of claims 1 to 3, wherein the target has an average crystal grain size of 50 or less. e-alloy sputtering target.

6. The Ge—In—Sb— for an optical recording medium according to any one of claims 1 to 5, wherein the iron content is 1 to 100 ppm. T e alloy sputtering target.