JPWO2005005683A1 - Sputtering target and optical recording medium - Google Patents
Sputtering target and optical recording medium Download PDFInfo
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- JPWO2005005683A1 JPWO2005005683A1 JP2005511456A JP2005511456A JPWO2005005683A1 JP WO2005005683 A1 JPWO2005005683 A1 JP WO2005005683A1 JP 2005511456 A JP2005511456 A JP 2005511456A JP 2005511456 A JP2005511456 A JP 2005511456A JP WO2005005683 A1 JPWO2005005683 A1 JP WO2005005683A1
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- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/24—Record carriers characterised by shape, structure or physical properties, or by the selection of the material
- G11B7/26—Apparatus or processes specially adapted for the manufacture of record carriers
- G11B7/266—Sputtering or spin-coating layers
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- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
- C23C14/22—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the process of coating
- C23C14/34—Sputtering
- C23C14/3407—Cathode assembly for sputtering apparatus, e.g. Target
- C23C14/3414—Metallurgical or chemical aspects of target preparation, e.g. casting, powder metallurgy
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- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/24—Record carriers characterised by shape, structure or physical properties, or by the selection of the material
- G11B7/241—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material
- G11B7/242—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of recording layers
- G11B7/243—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of recording layers comprising inorganic materials only, e.g. ablative layers
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- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/24—Record carriers characterised by shape, structure or physical properties, or by the selection of the material
- G11B7/241—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material
- G11B7/242—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of recording layers
- G11B7/243—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of recording layers comprising inorganic materials only, e.g. ablative layers
- G11B2007/24302—Metals or metalloids
- G11B2007/2431—Metals or metalloids group 13 elements (B, Al, Ga, In)
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- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/24—Record carriers characterised by shape, structure or physical properties, or by the selection of the material
- G11B7/241—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material
- G11B7/242—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of recording layers
- G11B7/243—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of recording layers comprising inorganic materials only, e.g. ablative layers
- G11B2007/24302—Metals or metalloids
- G11B2007/24312—Metals or metalloids group 14 elements (e.g. Si, Ge, Sn)
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/24—Record carriers characterised by shape, structure or physical properties, or by the selection of the material
- G11B7/241—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material
- G11B7/242—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of recording layers
- G11B7/243—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of recording layers comprising inorganic materials only, e.g. ablative layers
- G11B2007/24302—Metals or metalloids
- G11B2007/24314—Metals or metalloids group 15 elements (e.g. Sb, Bi)
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/24—Record carriers characterised by shape, structure or physical properties, or by the selection of the material
- G11B7/241—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material
- G11B7/242—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of recording layers
- G11B7/243—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of recording layers comprising inorganic materials only, e.g. ablative layers
- G11B2007/24302—Metals or metalloids
- G11B2007/24316—Metals or metalloids group 16 elements (i.e. chalcogenides, Se, Te)
Abstract
Ｇｅ（α）−Ｉｎ（β）−Ｓｂ（γ）−Ｔｅ（δ）合金からなるターゲットであって、各成分組成比α、β、γ、δ（原子％）の合計を１００としたとき、０．１≦α≦１０、０．１≦β≦１０、６０≦γ≦９０、１０≦δ＜２２の範囲にあることを特徴とする光記録媒体用Ｇｅ−Ｉｎ−Ｓｂ−Ｔｅ合金スパッタリングターゲット及び同合金からなる光記録媒体。スパッタリングの際にパーティクルの発生が少なく、安定して高品質の薄膜の作製が可能であり、記録ビットのエラー発生のない、そして高記録密度が達成できる光記録媒体用Ｇｅ−Ｉｎ−Ｓｂ−Ｔｅ合金スパッタリングターゲット及び同合金からなる光記録媒体を提供する。A target composed of a Ge(α)-In(β)-Sb(γ)-Te(δ) alloy, where the total of the component composition ratios α, β, γ, δ (atomic %) is 100, Ge-In-Sb-Te alloy sputtering target for optical recording medium, characterized by being in the range of 0.1≦α≦10, 0.1≦β≦10, 60≦γ≦90, 10≦δ<22. And an optical recording medium made of the same alloy. Ge-In-Sb-Te for optical recording media, which has few particles generated during sputtering, enables stable production of high-quality thin films, has no recording bit error, and can achieve high recording density. An alloy sputtering target and an optical recording medium made of the same alloy are provided.
Description
本発明は、スパッタリングターゲット及び同ターゲットの製造方法並びに光記録媒体に関し、特にスパッタリングの際にパーティクルの発生が少なく、安定して高品質の薄膜の作製が可能であり、記録ビットのエラー発生のない光記録媒体を得ることができるＧｅ−Ｉｎ−Ｓｂ−Ｔｅ合金スパッタリングターゲット及び同合金からなる光記録媒体に関する。 The present invention relates to a sputtering target, a method for manufacturing the same target, and an optical recording medium, and in particular, generation of particles is small during sputtering, a high-quality thin film can be stably manufactured, and an error of a recording bit does not occur. The present invention relates to a Ge-In-Sb-Te alloy sputtering target capable of obtaining an optical recording medium and an optical recording medium made of the same alloy.
近年、磁気ヘッドを必要とせずに記録・再生ができる高密度記録光ディスク技術が開発され、急速に関心が高まっている。この光ディスクは再生専用型、追記型、書き換え型の３種類に分けられるが、特に追記型又は書き換え型で使用されている相変化方式が注目されている。
相変化光ディスクは、基板上の記録薄膜をレーザー光の照射によって加熱昇温させ、その記録薄膜の構造に結晶学的な相変化（アモルファス⇔結晶）を起こさせて情報の記録・再生を行うものであり、より具体的にはその相間の光学定数の変化に起因する反射率の変化を検出して情報の再生を行うものである。
上記の相変化は１〜数μｍ程度の径に絞ったレーザー光の照射によって行なわれる。この場合、例えば１μｍのレーザービームが１０ｍ／ｓの線速度で通過するとき、光ディスクのある点に光が照射される時間は１００ｎｓであり、この時間内で上記相変化と反射率の検出を行う必要がある。
また、上記結晶学的な相変化すなわちアモルファスと結晶との相変化を実現する上で、これに適合する光記録媒体が求められている。一般に、ＤＶＤ−ＲＡＭ等の相変化光ディスクは、書き換え回数が１０５〜１０６回を保証している。
一方、基板への光記録媒体用薄膜を形成する場合、スパッタリングが使用されているが、ターゲットの材料によってパーティクルの発生が多くなり、品質を低下させる場合がある。特に高記録密度媒体ではパーティクルなどのよる記録ビットのエラー発生が深刻な問題となる。これが原因で、不良品となって歩留まりが低下するという問題が発生する。
従来、提案されている光記録媒体としては、Ｇｅ（α）−Ｉｎ（β）−Ｓｂ（γ）−Ｔｅ（δ）合金からなるターゲットで、各成分組成比α＋β＋γ＋δ（原子％）＝１００としたとき、０．１≦α≦７、１≦β≦９、６１≦γ≦７５、２２≦δ≦３０であり、ＣＬＶ記録及びＣＡＶ記録が可能とする光記録媒体が提案されている（特開２００２−２６４５１５号公報参照）。
また、ＧｅａＸｂＳｂｙＴｅ（１−ａ−ｂ−ｙ）と表したとき、ＸがＩｎ、Ａｕ、Ｃｕ、Ａｌ、Ｇａ、Ｐｂ、Ｔｉ、Ｓｎから選択される少なくとも一種の元素であり、０．００１≦ａ≦０．２０，０．０１≦ｂ≦０．２０，０．４０≦ｙ≦０．９０の範囲であると共に、記録層に窒素を含む光記録媒体が提案されている（特開２００２−２６４５１４号公報参照）。
また、Ｓｂ、Ｔｅを必須元素とし、このＳｂＴｅに対して少なくとも一種以上のＸ元素を添加した相変化光記録層であり、ＸがＡｇ、Ａｕ、Ｃｕ、Ｚｎ、Ｂ、Ａｌ、Ｇａ、Ｉｎ、Ｓｉ、Ｇｅ、Ｓｎ、Ｐｂ、Ｎ、Ｐ、Ｂｉ、Ｌａ、Ｃｅ、Ｃｄ、Ｔｂから選ばれるとする光記録媒体が提案されている（特開２００２−２４５６６３号公報参照）。
また、高純度Ｇｅ、もしくはＡｌ、Ｓｉ、Ｆｅ、Ｃｒ、Ｔａ、Ｎｂ、Ｃｕ、Ｍｎ、Ｍｏ、Ｗ、Ｎｉ、Ｔｉ、Ｚｒ、Ｈｆ、Ｃｏ、Ｉｒ、Ｐｔ、Ｒｕ、ＢおよびＣから選ばれる少なくとも１種の元素を０．１〜５０ａｔ原子％の範囲で含むＧｅ合金であって、ＡｇおよびＡｕ含有量がそれぞれ５ｐｐｍ以下である相変化光ディスク用スパッタリングターゲットが提案されている（特開２００２−６９６２４号公報参照）。In recent years, a high-density recording optical disc technology capable of recording/reproducing without the need for a magnetic head has been developed, and is rapidly gaining interest. This optical disc is classified into three types: a read-only type, a write-once type, and a rewritable type. In particular, the phase change method used in the write-once type or the rewritable type is drawing attention.
A phase-change optical disc is one in which information is recorded/reproduced by heating and heating the recording thin film on the substrate by irradiation of laser light to cause a crystallographic phase change (amorphous ⇔ crystal) in the structure of the recording thin film. More specifically, the information is reproduced by detecting the change in reflectance due to the change in the 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 μm. In this case, for example, when a laser beam of 1 μm passes at a linear velocity of 10 m/s, the time for irradiating a certain point on the optical disk with light is 100 ns, and the phase change and the reflectance are detected within this time. There is a need.
Further, in order to realize the above-mentioned crystallographic phase change, that is, the phase change between amorphous and crystalline, an optical recording medium suitable for this is required. Generally, a phase change optical disk such as a DVD-RAM guarantees a rewriting frequency of 10 5 to 10 6 .
On the other hand, when forming a thin film for an optical recording medium on a substrate, sputtering is used, but the generation of particles increases depending on the material of the target, which may deteriorate the quality. Particularly in a high recording density medium, the occurrence of recording bit errors due to particles or the like becomes a serious problem. Due to this, there arises a problem that the product becomes defective and the yield decreases.
A conventionally proposed optical recording medium is a target composed of a Ge(α)-In(β)-Sb(γ)-Te(δ) alloy, and the composition ratio of each component α+β+γ+δ (atomic %)=100. At this time, 0.1≦α≦7, 1≦β≦9, 61≦γ≦75, 22≦δ≦30, and an optical recording medium capable of CLV recording and CAV recording has been proposed (Japanese Patent Laid-Open No. 2003-242242). See Japanese Patent Laid-Open No. 2002-264515).
Also, when expressed Ge a X b Sb y Te and (1-a-b-y ), X is In, Au, Cu, Al, Ga, Pb, Ti, is at least one element selected from Sn , 0.001≦a≦0.20, 0.01≦b≦0.20, 0.40≦y≦0.90, and an optical recording medium containing nitrogen in the recording layer has been proposed. (See JP 2002-264514 A).
Further, it is a phase change optical recording layer in which Sb and Te are essential elements and at least one or more X elements are added to this SbTe, where X is Ag, Au, Cu, Zn, B, Al, Ga, In, An optical recording medium has been proposed which is selected from Si, Ge, Sn, Pb, N, P, Bi, La, Ce, Cd, and Tb (see Japanese Patent Laid-Open No. 2002-245663).
Further, high purity Ge or at least one selected from Al, Si, Fe, Cr, Ta, Nb, Cu, Mn, Mo, W, Ni, Ti, Zr, Hf, Co, Ir, Pt, Ru, B and C. There is proposed a sputtering target for a phase change optical disk, which is a Ge alloy containing one element in the range of 0.1 to 50 at% and has Ag and Au contents of 5 ppm or less, respectively (JP-A-2002-69624). (See the official gazette).
本発明は、スパッタリングの際にパーティクルの発生が少なく、安定して高品質の薄膜の作製が可能であり、記録ビットのエラー発生のない、そして高記録密度が達成できる光記録媒体用Ｇｅ−Ｉｎ−Ｓｂ−Ｔｅ合金スパッタリングターゲット及び同合金ターゲットの製造方法並びに同合金からなる光記録媒体を提供する。
上記の課題を解決するために、本発明者らは鋭意研究を行った結果、適切な組成のＧｅ−Ｉｎ−Ｓｂ−Ｔｅ合金を選択して高記録密度が達成すると共に、酸素含有量を厳しく制限し、かつ結晶粒度を厳密に調整することにより、スパッタリングの際にパーティクルの発生を効果的に抑制することができるとのとの知見を得た。
本発明はこの知見に基づき、
１．Ｇｅ（α）−Ｉｎ（β）−Ｓｂ（γ）−Ｔｅ（δ）合金からなるターゲットであって、各成分組成比α、β、γ、δ（原子％）の合計を１００としたとき、０．１≦α≦１０、０．１≦β≦１０、６０≦γ≦９０、１０≦δ＜２２の範囲にあることを特徴とする光記録媒体用Ｇｅ−Ｉｎ−Ｓｂ−Ｔｅ合金スパッタリングターゲット及び同合金からなる光記録媒体
２．酸素含有量が１５００ｐｐｍ以下であることを特徴とする上記１記載の光記録媒体用Ｇｅ−Ｉｎ−Ｓｂ−Ｔｅ合金スパッタリングターゲット及び同合金からなる光記録媒体
３．酸素含有量が８００ｐｐｍ以下であることを特徴とする上記１記載の光記録媒体用Ｇｅ−Ｉｎ−Ｓｂ−Ｔｅ合金スパッタリングターゲット及び同合金からなる光記録媒体
４．ターゲットの結晶平均粒度が１００μｍ以下であることを特徴とする上記１〜３のいずれかに記載の光記録媒体用Ｇｅ−Ｉｎ−Ｓｂ−Ｔｅ合金スパッタリングターゲット
５．ターゲットの結晶平均粒度が５０μｍ以下であることを特徴とする上記１〜３のいずれかに記載の光記録媒体用Ｇｅ−Ｉｎ−Ｓｂ−Ｔｅ合金スパッタリングターゲット
６．鉄の含有量が１〜１００ｐｐｍであることを特徴とする上記１〜５のいずれかに記載の光記録媒体用Ｇｅ−Ｉｎ−Ｓｂ−Ｔｅ合金スパッタリングターゲット
を提供する。The present invention is a Ge-In for optical recording medium in which few particles are generated during sputtering, a high-quality thin film can be stably manufactured, an error does not occur in a recording bit, and a high recording density can be achieved. Provided are an —Sb—Te alloy sputtering target, a method for manufacturing the same alloy target, and an optical recording medium made of the same alloy.
In order to solve the above problems, the inventors of the present invention have conducted diligent research, and as a result, selected a Ge—In—Sb—Te alloy having an appropriate composition to achieve a high recording density and strict oxygen content. It was found that the generation of particles during sputtering can be effectively suppressed by limiting and strictly adjusting the crystal grain size.
The present invention is based on this finding
1. A target composed of a Ge(α)-In(β)-Sb(γ)-Te(δ) alloy, where the total of the component composition ratios α, β, γ, δ (atomic %) is 100, Ge-In-Sb-Te alloy sputtering target for optical recording medium, characterized by being in the range of 0.1≦α≦10, 0.1≦β≦10, 60≦γ≦90, 10≦δ<22. And an optical recording medium composed of the same alloy 2. 2. The Ge-In-Sb-Te alloy sputtering target for an optical recording medium as described in 1 above, which has an oxygen content of 1500 ppm or less, and an optical recording medium comprising the same. 3. The Ge-In-Sb-Te alloy sputtering target for an optical recording medium according to the above 1, wherein the oxygen content is 800 ppm or less, and the optical recording medium comprising the same alloy. 4. The Ge-In-Sb-Te alloy sputtering target for an optical recording medium as described in any one of 1 to 3 above, wherein the target has a crystal average grain size of 100 μm or less. 5. The Ge-In-Sb-Te alloy sputtering target for an optical recording medium as described in any one of 1 to 3, wherein the target has a crystal average grain size of 50 μm or less. A Ge-In-Sb-Te alloy sputtering target for an optical recording medium according to any one of 1 to 5 above, wherein the iron content is 1 to 100 ppm.
本発明の光記録媒体用Ｇｅ−Ｉｎ−Ｓｂ−Ｔｅ合金スパッタリングターゲット及び同合金からなる光記録媒体は、スパッタリングの際にパーティクルの発生が少なく、安定して高品質の薄膜の作製が可能であり、記録ビットのエラー発生のない高記録密度が達成できるという優れた効果を有する。 The Ge-In-Sb-Te alloy sputtering target for an optical recording medium of the present invention and the optical recording medium made of the same alloy generate few particles during sputtering, and can stably produce a high-quality thin film. In addition, it has an excellent effect that a high recording density can be achieved with no recording bit error.
本発明の光記録媒体用Ｇｅ−Ｉｎ−Ｓｂ−Ｔｅ合金スパッタリングターゲット及び同合金からなる光記録媒体は、Ｇｅ（α）−Ｉｎ（β）−Ｓｂ（γ）−Ｔｅ（δ）合金からなり、各成分組成比α、β、γ、δ（原子％）の合計を１００としたとき、０．１≦α≦１０、０．１≦β≦１０、６０≦γ≦９０、１０≦δ＜２２の範囲にある。この合金組成は、高記録密度化が達成できる好適な組成であり、結晶学的な相変化すなわちアモルファスと結晶との相変化を実現し、書き換え回数の大幅な向上が可能となる。
さらに、本発明の光記録媒体用Ｇｅ−Ｉｎ−Ｓｂ−Ｔｅ合金スパッタリングターゲットは、酸素含有量が１５００ｐｐｍ以下に、より好ましくは８００ｐｐｍ以下に厳しく制限される。これによって、スパッタリングの際のパーティクル発生が著しく減少し、安定した高品質の薄膜の作製が可能であり、記録ビットのエラー発生のない、そして高記録密度が達成できる光記録媒体の製造が可能となる。
また、光記録媒体中の酸素はＧｅと選択的に結合するため、アモルファス化と結晶化の相互変態の安定性を劣化させ、繰り返し記録回数の低下をもたらす。したがって、光記録媒体中の酸素量の制限（極力減少させること）は高品質の膜が得る上でも重要である。
また、スパッタリングの際のパーティクル発生防止には、ターゲットの結晶平均粒度を１００μｍ以下とすることも極めて有効である。これによって、同様に記録ビットのエラー発生のない良好な薄膜の作製が可能となる。特に、ターゲットの結晶平均粒度が５０μｍ以下であることが望ましい。
さらに、本発明の光記録媒体用Ｇｅ−Ｉｎ−Ｓｂ−Ｔｅ合金スパッタリングターゲット（記録媒体）中に鉄の含有量を１〜１００ｐｐｍとすることが有効である。１ｐｐｍ未満では添加の効果がなく、１００ｐｐｍを超えるとＣＮＲとＤＯＷが悪くなるので、鉄を添加する場合には、Ｆｅの含有量を１〜１００ｐｐｍとするのが望ましい。
本発明の光記録媒体用Ｇｅ−Ｉｎ−Ｓｂ−Ｔｅ合金スパッタリングターゲットは、Ｇｅ粉、Ｉｎ粉、Ｓｂ粉、Ｔｅ粉をアンプル内で合成し、得られたインゴットを所定の粒度まで粉砕した後、均一に分散混合させた後ホットプレスを使用して、焼結温度４００〜６００°Ｃ、面圧７５〜２５０ｋｇ／ｃｍ２の条件で焼結することによって製造することができる。The Ge-In-Sb-Te alloy sputtering target for an optical recording medium of the present invention and the optical recording medium made of the same alloy are made of Ge(α)-In(β)-Sb(γ)-Te(δ) alloy, When the total of the component composition ratios α, β, γ, δ (atomic %) is 100, 0.1≦α≦10, 0.1≦β≦10, 60≦γ≦90, 10≦δ<22 Is in the range. This alloy composition is a suitable composition capable of achieving a high recording density, realizes a crystallographic phase change, that is, a phase change between amorphous and crystal, and can remarkably improve the number of times of rewriting.
Furthermore, the Ge-In-Sb-Te alloy sputtering target for an optical recording medium of the present invention is severely limited to an oxygen content of 1500 ppm or less, more preferably 800 ppm or less. This significantly reduces the generation of particles during sputtering, enables stable production of high-quality thin films, does not cause recording bit errors, and enables the manufacture of optical recording media that can achieve high recording density. Become.
In addition, since oxygen in the optical recording medium is selectively combined with Ge, the stability of mutual transformation between amorphization and crystallization is deteriorated and the number of repeated recordings is reduced. Therefore, limiting the oxygen amount in the optical recording medium (reducing it as much as possible) is important for obtaining a high quality film.
Further, in order to prevent particles from being generated during sputtering, it is also extremely effective to set the average crystal grain size of the target to 100 μm or less. As a result, it becomes possible to manufacture a good thin film without causing the recording bit error. In particular, it is desirable that the target has a crystal average grain size of 50 μm or less.
Furthermore, it is effective to set the iron content in the Ge-In-Sb-Te alloy sputtering target (recording medium) for an optical recording medium of the present invention to 1 to 100 ppm. If it is less than 1 ppm, there is no effect of addition, and if it exceeds 100 ppm, CNR and DOW deteriorate. Therefore, when iron is added, it is preferable that the content of Fe be 1 to 100 ppm.
The Ge-In-Sb-Te alloy sputtering target for an optical recording medium of the present invention is obtained by synthesizing Ge powder, In powder, Sb powder and Te powder in an ampoule, and crushing the obtained ingot to a predetermined particle size, It can be produced by uniformly dispersing and mixing, and then using a hot press to sinter at a sintering temperature of 400 to 600° C. and a surface pressure of 75 to 250 kg/cm 2 .
以下、実施例および比較例に基づいて説明する。なお、本実施例はあくまで一例であり、この例によって何ら制限されるものではない。すなわち、本発明は特許請求の範囲によってのみ制限されるものであり、本発明に含まれる実施例以外の種々の変形を包含するものである。
［実施例１−７］
純度５Ｎ（９９．９９９％）のＧｅ粉、Ｉｎ粉、Ｓｂ粉、Ｔｅ粉を準備し、これらの粉をＧｅ（α）−Ｉｎ（β）−Ｓｂ（γ）−Ｔｅ（δ）となるように調合した後アンプル内で合成し、得られたインゴットを所定の粒度まで粉砕した後、カーボン製ダイスに充填し、温度６００°Ｃ、圧力１５０ｋｇ／ｃｍ２の条件でホットプレスを行った。
この焼結体を仕上げ加工してターゲットとした。ターゲットの相対密度は９９％（１００％密度で５．５４ｇ／ｃｍ３）であった。このターゲットの３箇所から任意に採取したサンプルの密度をアルキメデス法により測定した。
また、同組成におけるＴｅ含有量δ（ａｔ％）、酸素量（ｗｔｐｐｍ）、粒径（μｍ）、Ｆｅ含有量、ＣＮＲ（ｃａｒｒｉｅｒ ｔｏ ｎｏｉｓｅ ｒａｔｉｏ）、ＤＯＷ（ｄｉｒｅｃｔ ｏｖｅｒ ｗｒｉｔｅ）、スパッタリング時のパーティクル発生の結果を表１に示す。
なお、ＣＮＲ（ｄＢ）は３０ｍ／ｓにおける測定値、ＤＯＷは１００回上書き記録を実施した時点でのジッターによる評価結果を示す。ジッターとは最小ピット長信号（３Ｔ）の最大ピット長信号（１１Ｔ）に対する再信号のずれの値で、今回は２０％を下回るものをＯＫ、２０％以上をＮＧと判定した。
また、評価サンプルは、ＤＶＤブランクメディア上に、ＺｎＳ−ＳｉＯ２（４５ｎｍ）、記録層（１５ｎｍ）、ＺｎＳ−ＳｉＯ２（２０ｎｍ）、Ａｌ−Ｔｉ（１５０ｎｍ）を連続成膜して作製した。
比較例
（比較例１−６）
純度５Ｎ（９９．９９９％）のＧｅ粉、Ｉｎ粉、Ｓｂ粉、Ｔｅ粉を準備し、これらの粉をＧｅ（α）−Ｉｎ（β）−Ｓｂ（γ）−Ｔｅ（δ）となるように調合し、これを乾式混合した後アンプル内で合成し、得られたインゴットを所定の粒度まで粉砕した後、カーボン製ダイスに充填し、温度６００°Ｃ、圧力１５０ｋｇ／ｃｍ２の条件でホットプレスを行った。
この焼結体を仕上げ加工してターゲットとした。ターゲットの相対密度は９９％（１００％密度で５．５４ｇ／ｃｍ３）であった。このターゲットの３箇所から任意に採取したサンプルの密度をアルキメデス法により測定した。
また、同組成におけるＴｅ含有量δ（ａｔ％）、酸素量（ｗｔｐｐｍ）、粒径（μｍ）、Ｆｅ含有量、ＣＮＲ（ｄＢ）、ＤＯＷ、スパッタリング時のパーティクル発生の結果を、実施例と対比し表１に示す。なお、ＣＮＲ（ｄＢ）測定値、ＤＯＷ測定値、評価サンプルのスパッタリング条件は、実施例と同様に行った。
なお、実施例７については、Ｆｅ含有量が＜１ｗｔｐｐｍであるが、原料に含まれる酸素含有量が５００ｐｐｍ以下（４５０ｗｔｐｐｍ）と低いので、上記と同様にＣＮＲ（ｄＢ）、ＤＯＷ、パーティクル発生量はいずれも良好であった。
これに対し、比較例１は酸素量が２０００ｐｐｍと多いためＤＯＷ、パーティクル発生量は不良であった。比較例２は、粒径が２００μｍと大きいためパーティクル発生量は不良であった。比較例３は、Ｆｅ含有量が１２０ｐｐｍと多過ぎるため、ＤＯＷが悪化した。比較例４は、酸素含有量が２５００ｐｐｍと多く、またＦｅ＜１ｐｐｍのため、ＤＯＷ、パーティクル発生量は不良であった。Ｆｅがない場合には酸素が高くなる。比較例５は、δ２２．０ａｔ％と組成ずれを生じている（過量の）ため、ＤＯＷが不良であった。比較例６はδ５．０ａｔ％と組成ずれを生じている（過少）のため、ＤＯＷが不良であった。
以上に示すように、Ｇｅ（α）−Ｉｎ（β）−Ｓｂ（γ）−Ｔｅ（δ）合金からなるターゲットにおいて、Ｔｅ（δ）組成のずれは、光記録媒体の特性に大きく影響を与えることが分かる。
また、ターゲットの酸素量、粒径は、本発明の範囲において、良好なＣＮＲ（ｄＢ）とＤＯＷ及びパーティクル発生の抑制効果を有する。また、Ｆｅ含有量は酸素量に影響を与え、適量のＦｅの存在はスパッタリング時のパーティクル発生の抑制効果を有する。また、酸素量が十分に低い場合には、Ｆｅ含有量に関係なく、同様の良好な結果を示すことが分かる。Hereinafter, it demonstrates based on an Example and a comparative example. It should be noted that the present embodiment is merely an example, and the present invention is not limited thereto. That is, the present invention is limited only by the scope of the claims, and includes various modifications other than the embodiments included in the present invention.
[Example 1-7]
Prepare Ge powder, In powder, Sb powder, and Te powder having a purity of 5N (99.999%) so that these powders become Ge(α)-In(β)-Sb(γ)-Te(δ). After being blended in an ampoule, the obtained ingot was crushed to a predetermined particle size, then charged into a carbon die, and hot pressed under the conditions of a temperature of 600° C. and a pressure of 150 kg/cm 2 .
This sintered body was finished and used as a target. The relative density of the target was 99% (5.54 g/cm 3 at 100% density). The densities of samples arbitrarily collected from three points of this target were measured by the Archimedes method.
Further, Te content δ (at %), oxygen content (wtppm), particle size (μm), Fe content, CNR (carrier to noise ratio), DOW (direct over write), and particle generation during sputtering in the same composition The results are shown in Table 1.
In addition, CNR (dB) shows a measured value at 30 m/s, and DOW shows an evaluation result by jitter at the time of performing overwriting recording 100 times. Jitter is the value of the deviation of the re-signal from the minimum pit length signal (3T) with respect to the maximum pit length signal (11T), and this time, it was determined that those below 20% were OK, and those above 20% were NG.
The evaluation sample, on the DVD blank media, ZnS-SiO 2 (45nm) , the recording layer (15nm), ZnS-SiO 2 (20nm), was prepared by continuously forming the Al-Ti (150nm).
Comparative Example (Comparative Example 1-6)
Prepare Ge powder, In powder, Sb powder, and Te powder having a purity of 5N (99.999%) so that these powders become Ge(α)-In(β)-Sb(γ)-Te(δ). The resulting ingot was pulverized to a predetermined particle size and then filled in a carbon die and hot at a temperature of 600°C and a pressure of 150 kg/cm 2. I made a press.
This sintered body was finished and used as a target. The relative density of the target was 99% (5.54 g/cm 3 at 100% density). The densities of samples arbitrarily collected from three points of this target were measured by the Archimedes method.
In addition, the results of Te content δ (at %), oxygen content (wtppm), particle size (μm), Fe content, CNR (dB), DOW, and particle generation during sputtering in the same composition are compared with the examples. The results are shown in Table 1. The CNR (dB) measurement value, the DOW measurement value, and the sputtering conditions for the evaluation sample were the same as in the example.
In addition, in Example 7, the Fe content is <1 wtppm, but the oxygen content contained in the raw material is as low as 500 ppm or less (450 wtppm). All were 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 μm, the amount of particles generated was poor. In Comparative Example 3, the Fe content was 120 ppm, which was too large, and thus the DOW deteriorated. In Comparative Example 4, the oxygen content was as high as 2500 ppm and Fe<1 ppm, so the DOW and particle generation amount were poor. In the absence of Fe, oxygen will be high. In Comparative Example 5, the composition shift was generated at δ22.0 at% (excessive amount), and thus the DOW was poor. Comparative Example 6 had a composition deviation of δ 5.0 at% (too small), and thus had poor DOW.
As described above, in the target composed of the Ge(α)-In(β)-Sb(γ)-Te(δ) alloy, the deviation of the Te(δ) composition greatly affects the characteristics of the optical recording medium. I understand.
Further, the oxygen amount and the particle size of the target have good CNR (dB) and DOW and the effect of suppressing the generation of particles within the range of the present invention. Further, the Fe content affects the oxygen content, and the presence of an appropriate amount of Fe has the effect of suppressing the generation of particles during sputtering. Further, it can be seen that when the oxygen amount is sufficiently low, the same good result is exhibited regardless of the Fe content.
本発明は、スパッタリングの際にパーティクルの発生が少なく、安定して高品質の薄膜の作製が可能であり、記録ビットのエラー発生のない、そして高記録密度が達成できる光記録媒体用Ｇｅ−Ｉｎ−Ｓｂ−Ｔｅ合金スパッタリングターゲット及び同合金ターゲットの製造方法並びに同合金からなる光記録媒体に適用できる。 The present invention is a Ge-In for optical recording medium in which few particles are generated during sputtering, a high-quality thin film can be stably manufactured, an error does not occur in a recording bit, and a high recording density can be achieved. The present invention can be applied to a —Sb—Te alloy sputtering target, a method for producing the same alloy target, and an optical recording medium made of the same alloy.
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| PCT/JP2004/005395 WO2005005683A1 (en) | 2003-07-15 | 2004-04-15 | Sputtering target and optical recording medium |
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| JP2009197310A (en) | 2008-02-25 | 2009-09-03 | Kobe Steel Ltd | Sputtering target |
| JP2009221588A (en) * | 2008-03-19 | 2009-10-01 | Mitsubishi Materials Corp | Sputtering target for phase change film formation with less particle generation |
| JP5045804B2 (en) * | 2009-10-29 | 2012-10-10 | 住友金属鉱山株式会社 | Sputtering target for forming a resistance thin film, resistance thin film, thin film resistor, and manufacturing method thereof |
| JP5153911B2 (en) | 2011-04-22 | 2013-02-27 | 三菱マテリアル株式会社 | Sputtering target and manufacturing method thereof |
| KR20160078478A (en) | 2014-03-25 | 2016-07-04 | 제이엑스금속주식회사 | Sputtering target of sintered sb-te-based alloy |
| JP7261694B2 (en) * | 2019-08-09 | 2023-04-20 | Ｊｘ金属株式会社 | Sputtering target and method for manufacturing sputtering target |
| CN114892133A (en) * | 2022-04-02 | 2022-08-12 | 昆明贵研新材料科技有限公司 | Ru-Sb-Te alloy sputtering target material used as long-storage phase change storage medium and preparation method thereof |
| CN114717524A (en) * | 2022-04-02 | 2022-07-08 | 昆明贵研新材料科技有限公司 | Ru-Sb-Te alloy sputtering target material suitable for serving as long-storage phase change storage medium and preparation method thereof |
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| JP4582457B2 (en) | 2010-11-17 |
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