JP3339137B2 - Synthetic diamond single crystal and method for producing the same - Google Patents

Synthetic diamond single crystal and method for producing the same

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Publication number
JP3339137B2
JP3339137B2 JP26904093A JP26904093A JP3339137B2 JP 3339137 B2 JP3339137 B2 JP 3339137B2 JP 26904093 A JP26904093 A JP 26904093A JP 26904093 A JP26904093 A JP 26904093A JP 3339137 B2 JP3339137 B2 JP 3339137B2
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JP
Japan
Prior art keywords
crystal
nitrogen
boron
synthetic diamond
diamond
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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JP26904093A
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Japanese (ja)
Other versions
JPH07116494A (en
Inventor
均 角谷
周一 佐藤
良樹 西林
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Sumitomo Electric Industries Ltd
Original Assignee
Sumitomo Electric Industries Ltd
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Application filed by Sumitomo Electric Industries Ltd filed Critical Sumitomo Electric Industries Ltd
Priority to JP26904093A priority Critical patent/JP3339137B2/en
Priority to KR1019940025640A priority patent/KR100269924B1/en
Priority to EP94307418A priority patent/EP0647590B1/en
Priority to DE69411244T priority patent/DE69411244T2/en
Publication of JPH07116494A publication Critical patent/JPH07116494A/en
Priority to US08/684,725 priority patent/US6030595A/en
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Publication of JP3339137B2 publication Critical patent/JP3339137B2/en
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Expired - Lifetime legal-status Critical Current

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Description

【発明の詳細な説明】DETAILED DESCRIPTION OF THE INVENTION

【０００１】[0001]

【産業上の利用分野】本発明は光学部品、分光結晶、モ
ノクロメーター、レーザー用窓材、放射光または放射線
用窓材、アンビル、半導体基板もしくは装飾用途などに
用いられる無色透明で歪み等の少ない高純度で結晶性の
良い合成ダイヤモンドとその製造方法に関するものであ
る。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical component, a spectral crystal, a monochromator, a window material for a laser, a window material for radiation or radiation, an anvil, a semiconductor substrate, and a colorless transparent material having little distortion and the like. The present invention relates to a synthetic diamond having high purity and good crystallinity and a method for producing the same.

【０００２】[0002]

【従来の技術】ダイヤモンドは高硬度、高強度で熱伝導
性、耐食性にも優れ、光の透過性がよい。このことから
ダイヤモンド結晶は、ヒートシンク、線引き用ダイス、
精密加工用バイト、光学部品、レーザー窓、超高圧発生
用アンビルなど幅広い用途に適用されている。天然に産
出するダイヤモンドは、その殆どがＩａ型と呼ばれ、窒
素を１０００ｐｐｍ程度含む。この天然ダイヤモンド中
の窒素は凝集した形で結晶内に分布するため、結晶欠陥
や内部歪みが大きく、また、赤外領域にこの窒素による
光の吸収がある。また原石により、バラツキが大きい。
そのため、適用できる用途がヒートシンクや工具関係に
限られていた。また、天然ダイヤモンドで窒素不純物が
数ｐｐｍ以下の高純度品はIIａ型と呼ばれ、このような
ダイヤモンドは天然産出総量の約２％程度と稀少なもの
である。天然のIIａ型ダイヤモンドは不純物が少なく、
無色透明で光の透過特性が優れているため、装飾用途や
光学部品、レーザー窓材等に用いられている。しかしな
がら、地球内部での複雑な成長過程を経てきたことを反
映し、結晶内部に欠陥や、歪みがかなり多く残留する。
歪みに関しては、窒素を含む合成ダイヤモンドよりむし
ろ多い。また、天然のIIａ型は産出量が少なく、極めて
高価なもので、入手にかなり問題がある。2. Description of the Related Art Diamond has high hardness, high strength, excellent thermal conductivity and corrosion resistance, and good light transmission. From this, the diamond crystal can be used as a heat sink, wire drawing die,
It is applied to a wide range of applications, such as precision machining tools, optical components, laser windows, and anvils for generating ultra-high pressure. Most of naturally occurring diamonds are called type Ia and contain about 1000 ppm of nitrogen. Since nitrogen in the natural diamond is distributed in the crystal in an aggregated form, crystal defects and internal strain are large, and light is absorbed by the nitrogen in an infrared region. Also, there are large variations due to the rough.
Therefore, applicable applications are limited to heat sinks and tools. High-purity natural diamonds having a nitrogen impurity of several ppm or less are called type IIa, and such diamonds are rare, about 2% of the total amount of natural production. Natural type IIa diamond has few impurities,
Since it is colorless and transparent and has excellent light transmission characteristics, it is used for decorative applications, optical components, laser window materials, and the like. However, reflecting the complex growth process inside the earth, many defects and strains remain inside the crystal.
With respect to distortion, it is more than a synthetic diamond containing nitrogen. In addition, natural type IIa has a low yield, is extremely expensive, and has a considerable problem in obtaining it.

【０００３】超高圧高温下で人工的に合成される通常の
ダイヤモンドはＩｂ型と呼ばれ、数１００ｐｐｍの窒素
を含む。この窒素は、ダイヤモンド結晶中に孤立置換型
不純物として含まれるため、結晶は黄色を呈し、装飾用
としては価値が低い。また、赤外領域および紫外領域に
窒素による光の吸収があり、光学部品や窓材には使えな
い。そして、成長セクターにより窒素の濃度が極端に異
なり、結晶内部で窒素の分布に大きなムラがある。その
ため結晶内に歪みが多い。一方、ダイヤモンド合成時に
溶媒金属中にＡｌなどの窒素ゲッターを添加することに
より、合成されたダイヤモンド中の窒素を数ｐｐｍ程度
にまで除去できて合成IIａ型ダイヤモンドを得ることが
知られている。しかし、窒素ゲッターを溶媒金属中に添
加すると、通常は結晶中に内包物が多く取り込まれやす
くなり、良質な結晶の製造歩留りが大きく低下する。こ
のため、従来の合成IIａ型ダイヤモンドは天然のIIａ型
ダイヤモンドより製造コストが高くなっていた。また、
合成ダイヤモンド中の窒素の除去も１ｐｐｍ程度が限度
で、装飾用としての評価もＧＩＡスケールでＨ〜Ｊ程度
であった（特開昭５２−８８２８９号公報）。また、紫
外域に窒素による吸収があった。[0003] Ordinary diamond artificially synthesized under ultra-high pressure and high temperature is called type Ib and contains several hundred ppm of nitrogen. Since this nitrogen is contained in the diamond crystal as an isolated substitutional impurity, the crystal has a yellow color and is of low value for decoration. Further, nitrogen absorbs light in the infrared region and the ultraviolet region and cannot be used for optical components and window materials. The concentration of nitrogen is extremely different depending on the growth sector, and there is a large unevenness in the distribution of nitrogen inside the crystal. Therefore, there are many distortions in the crystal. On the other hand, it is known that by adding a nitrogen getter such as Al to a solvent metal during diamond synthesis, nitrogen in the synthesized diamond can be removed to about several ppm to obtain a synthetic IIa type diamond. However, when a nitrogen getter is added to the solvent metal, a large amount of inclusions are usually easily incorporated into the crystal, and the production yield of high-quality crystals is greatly reduced. For this reason, the production cost of the conventional synthetic type IIa diamond was higher than that of natural type IIa diamond. Also,
The removal of nitrogen from synthetic diamond was also limited to about 1 ppm, and the evaluation for decoration was about H to J on the GIA scale (JP-A-52-88289). Further, there was absorption by nitrogen in the ultraviolet region.

【０００４】さらに窒素ゲッターとして、ＴｉやＺｒな
どの元素を用いることが知られている。これらを窒素ゲ
ッターとすると窒素は効率良く除去できるものの、Ｔｉ
ＣやＺｒＣなどの炭化物が溶媒中に多量に生成し、それ
がダイヤモンド結晶中に取り込まれて良質なダイヤモン
ドは殆ど得られなかった。これに対し、本発明者等は、
窒素除去効率の高いIVａ族およびＶａ族元素から選ばれ
る少なくとも１種以上を窒素ゲッターとして用い、同時
に内包物が結晶中に取り込まれないように、IVａ族元素
の炭化物の生成を抑制する物質や、炭化物を拡散させる
物質、または溶媒金属中の炭素の活量を向上させる物質
を溶媒金属中に添加することにより、窒素含有量０．１
ｐｐｍ以下の内包物のないIIａ型合成ダイヤモンドの製
造に成功した。しかし、結晶中にはやはり数ｐｐｍのホ
ウ素が含まれ、そのため赤外領域にホウ素による光の吸
収があり、また結晶内に若干の歪みや欠陥もあった。It is known that an element such as Ti or Zr is used as a nitrogen getter. If these are used as nitrogen getters, nitrogen can be removed efficiently, but Ti
A large amount of carbides such as C and ZrC were generated in the solvent, and these were incorporated into the diamond crystal, and almost no high-quality diamond was obtained. In contrast, the present inventors,
A substance that suppresses the formation of carbides of the IVa group element, so that at least one selected from the group IVa and Va group elements having high nitrogen removal efficiency is used as a nitrogen getter, and at the same time, inclusions are not taken into the crystal. By adding a substance that diffuses carbide or a substance that improves the activity of carbon in the solvent metal to the solvent metal, the nitrogen content is reduced to 0.1.
We succeeded in producing type IIa synthetic diamond without inclusions of less than ppm. However, the crystal still contained several ppm of boron, so that light was absorbed by boron in the infrared region, and there were some distortions and defects in the crystal.

【０００５】[0005]

【発明が解決しようとする課題】上記のように天然のダ
イヤモンドは、結晶内部に多くの欠陥や大きな歪みがあ
る。天然IIａ型ダイヤモンドは不純物が少ないものの、
欠陥や歪みなどの結晶性に関しては良くない。そのた
め、加工中に亀裂が入りやすく、また、超高圧発生用ア
ンビル、ＦＴ−ＩＲ用コンプレッションセル、レーザー
の窓材など、ダイヤモンドとしての強度を必要とする分
野に用いると、場合によっては直ぐに壊れてしまうとい
う問題があった。また、モノクロメーターや半導体基板
などは高度な結晶性が要求されるため、この分野には適
用できなかった。一方、人工合成によるIIａ型ダイヤモ
ンドは結晶性に関しては天然のものに比べてはるかに優
れているものの、充分とはいえず、加工歩留りが低いこ
と、ダイヤモンド本来の特性と比べると機械的強度が低
いこと、モノクロメーターや半導体基板などの結晶性を
要求される用途には適用できないなどの問題があった。
また、従来の合成IIａ型ダイヤモンド結晶には数ｐｐｍ
のホウ素が含まれ、そのため赤外領域にホウ素による光
の吸収があり、光学部品としての応用に問題があった。
また、結晶内に若干の歪みや欠陥も存在した。すなわ
ち、温度差法によるダイヤモンドの合成においては、炭
素源にダイヤモンド粉末を用いるが、市販の合成ダイヤ
モンド粉末には１０〜１０００ｐｐｍのホウ素を含み、
天然ダイヤモンド粉末にも数十から数百ｐｐｍのホウ素
を含みバラツキも大きい。このような炭素源を用いてダ
イヤモンドを合成すると、結晶中には数ｐｐｍ〜十数ｐ
ｐｍのホウ素を含有し、結晶は青色を呈する。このた
め、赤外領域および紫外〜可視領域にホウ素による吸収
があり、光学部品としては好ましくない。また、結晶の
成長セクターによりホウ素の濃度が極端に異なるなど、
結晶内部でのホウ素の分布に大きなムラがある。この点
が結晶性の良くない理由の一つであると考えられる。こ
のホウ素をほぼ完全に除去することで無色透明でかつ歪
みや欠陥の少ない結晶が得られるが、炭素源や溶媒の原
料に非常に純度の高いものを用いる必要があり、原料供
給、コストの点で問題があった。本発明はこのような問
題点を解決した合成ダイヤモンド単結晶およびその製造
方法を提供することを目的とする。As described above, natural diamond has many defects and large distortion inside the crystal. Although natural IIa type diamond has few impurities,
Crystallinity such as defects and distortion is not good. For this reason, cracks are likely to occur during processing, and when used in fields that require the strength of diamond, such as an anvil for generating ultra-high pressure, a compression cell for FT-IR, and a window material for laser, it may be quickly broken in some cases. There was a problem that it would. Further, monochromators, semiconductor substrates, and the like require high crystallinity, and thus cannot be applied to this field. On the other hand, type IIa diamonds made by artificial synthesis are far superior to natural ones in terms of crystallinity, but they are not sufficient, have low processing yields, and have low mechanical strength compared to the original characteristics of diamonds. In addition, it cannot be applied to applications requiring crystallinity such as a monochromator and a semiconductor substrate.
In addition, conventional synthetic IIa type diamond crystals have several ppm
Therefore, there is a problem in the application as an optical component due to the absorption of light by the boron in the infrared region.
There were also some distortions and defects in the crystals. That is, in the synthesis of diamond by the temperature difference method, diamond powder is used as a carbon source, but commercially available synthetic diamond powder contains 10 to 1000 ppm of boron,
Natural diamond powder also contains tens to hundreds of ppm of boron and has large variations. When diamond is synthesized using such a carbon source, several ppm to more than ten p
It contains pm of boron and the crystals exhibit a blue color. For this reason, there is absorption by boron in the infrared region and the ultraviolet to visible region, which is not preferable as an optical component. Also, the concentration of boron is extremely different depending on the crystal growth sector.
There is a large unevenness in the distribution of boron inside the crystal. This is considered to be one of the reasons for poor crystallinity. By removing this boron almost completely, a crystal that is colorless and transparent and has few distortions and defects can be obtained. There was a problem. An object of the present invention is to provide a synthetic diamond single crystal that solves such a problem and a method for producing the same.

【０００６】[0006]

【課題を解決するための手段】上記の課題を解決する本
発明は、(1) 結晶中に窒素原子およびホウ素原子を含有
し、該窒素原子数と該ホウ素原子数がほぼ同じ程度で、
且つ前記窒素原子数と前記ホウ素原子数との差が１×１
０17原子／ｃｍ3 以下であることを特徴とする合成ダイ
ヤモンド単結晶を提供し、さらに本発明は(2) 結晶中に
窒素原子およびホウ素原子を含有し、該窒素原子数と該
ホウ素原子数がほぼ同じ程度で、且つ前記窒素原子数と
前記ホウ素原子数との差が１×１０16原子／ｃｍ3 以下
であることを特徴とする合成ダイヤモンド単結晶を提供
する。また、上記(1) 、(2) の合成ダイヤモンド単結晶
の製造方法に関し、本発明は超高温高圧下の温度差法に
よるダイヤモンド単結晶の合成方法において、合成中に
結晶内に取り込まれる窒素量とホウ素量が原子数でほぼ
同じ程度になるよう、溶媒金属中に添加する窒素ゲッタ
ーの添加量を調整する、または炭素源もしくは溶媒金属
中に添加するホウ素の添加量を調整することを特徴とす
る製造方法を提供するものである。The present invention for solving the above-mentioned problems is characterized in that (1) the crystal contains a nitrogen atom and a boron atom, and the number of the nitrogen atoms and the number of the boron atoms are substantially the same;
And the difference between the number of nitrogen atoms and the number of boron atoms is 1 × 1
0 17 atoms / cm 3 to provide a synthetic diamond single crystal, characterized in that less, further the present invention contains a nitrogen atom and boron atom in (2) in the crystal, nitride number atom and the number of the boron atoms Are substantially the same, and the number of nitrogen atoms is
Provided is a synthetic diamond single crystal , wherein the difference from the number of boron atoms is 1 × 10 16 atoms / cm 3 or less. The present invention also relates to a method for producing a synthetic diamond single crystal according to the above (1) or (2), wherein the present invention relates to a method for synthesizing a diamond single crystal by a temperature difference method under ultra-high pressure and high temperature. Adjust the amount of nitrogen getter added to the solvent metal , or add boron to the carbon source or the solvent metal so that the amount of nitrogen and the amount of boron to be taken in become approximately the same in terms of the number of atoms. It is intended to provide a production method characterized by adjusting the amount.

【０００７】[0007]

【作用】上記の問題を解決するため鋭意研究の結果、本
発明者等は窒素をある程度ダイヤモンド中に残すことに
より原料に由来するホウ素不純物による青色化、結晶性
の低下を窒素で補償できるという事実を見いだした。そ
の結果、窒素除去量をコントロールすることによりホウ
素および窒素を含むが、光学的にホウ素や窒素の吸収の
ない無色透明なダイヤモンドおよびこれを製造できる本
発明の方法に到達した。また、本発明によれば、ホウ素
による結晶中の歪みも緩和され、結晶性も改善されるこ
とを見いだした。また更に、Ａｌなどの窒素ゲッターを
用いた場合、ダイヤモンド中の窒素をほぼ完全に除去す
るのには困難を要するが、この場合には除去しきれずに
残した窒素量と同程度のホウ素を結晶中に添加すると、
ホウ素および窒素を含むが、光学的にホウ素や窒素の吸
収のない無色透明なガラスが得られることが判った。ま
た、窒素による結晶中の歪みも緩和され、結晶性も改善
されることを見いだした。As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that by leaving nitrogen to some extent in diamond, it is possible to compensate for bluening and crystallinity deterioration due to boron impurities derived from the raw material with nitrogen. Was found. As a result, a colorless and transparent diamond which contains boron and nitrogen by controlling the nitrogen removal amount but does not absorb boron or nitrogen optically, and a method of the present invention capable of producing the same has been achieved. Further, according to the present invention, it has been found that the strain in the crystal due to boron is alleviated and the crystallinity is also improved. Furthermore, when a nitrogen getter such as Al is used, it is difficult to remove nitrogen in diamond almost completely, but in this case, boron having the same amount as the amount of nitrogen remaining without being removed is crystallized. When added inside,
It was found that a colorless and transparent glass containing boron and nitrogen but having no optical absorption of boron or nitrogen was obtained. In addition, the inventors have found that the strain in the crystal due to nitrogen is alleviated and the crystallinity is also improved.

【０００８】この点を更に詳しく説明する。Ｆｅ−Ａｌ
系溶媒で合成するとＡｌの反応（Ａｌ＋Ｎ＝ＡｌＮ）が
弱く結晶中の窒素除去効果が低い。これに対しＴｉを溶
媒に添加すると窒素の含有量が０．１ｐｐｍ以下で内包
物の殆どない高品質な高純度ダイヤモンドを合成でき
た。しかし、Ｔｉゲッターで合成したダイヤにはＡｌゲ
ッターでは現れなかった赤外や近赤外にホウ素の吸収が
現れた（含有量０．２ｐｐｍ前後）。このことから、ｐ
型半導体（アクセプター）として作用するホウ素と、ｎ
型半導体（ドナー）として作用する窒素が結晶合成中に
ＡＤペアーを生じ電気的に中和する為、窒素およびホウ
素に起因する吸収が消滅するであろうと推定した。すな
わち、Ａｌゲッターで合成した場合、窒素の除去効果が
低いため、結晶中に取り込まれるホウ素と程良く電気的
に中和されて吸収が低減するが、窒素ゲッターを用いる
と窒素がほぼ完全に除去されてしまい、取り込まれたホ
ウ素の吸収のみが現れると考えた。この効果を確認する
ために、窒素が比較的多く残存する合成条件でホウ素を
積極的に添加して合成を試みた。その結果、ホウ素の含
有量が多い（１１１）セクターで、紫外におけるＩｂ型
窒素の吸収（４．６ｅＶにおける）が大幅に減少した。[0008] This point will be described in more detail. Fe-Al
When synthesized with a system solvent, the reaction of Al (Al + N = AlN) is weak, and the effect of removing nitrogen from the crystal is low. On the other hand, when Ti was added to the solvent, a high-quality high-purity diamond having a nitrogen content of 0.1 ppm or less and almost no inclusions could be synthesized. However, in the diamond synthesized with the Ti getter, the absorption of boron appeared in the infrared and near infrared which did not appear in the Al getter (content: about 0.2 ppm). From this, p
Boron acting as a type semiconductor (acceptor) and n
It was presumed that absorption due to nitrogen and boron would disappear because nitrogen acting as a type semiconductor (donor) forms an AD pair during crystal synthesis and is electrically neutralized. In other words, when synthesized with an Al getter, the effect of removing nitrogen is low, so that boron is sufficiently neutralized electrically with boron incorporated in the crystal and absorption is reduced. However, nitrogen is almost completely removed by using a nitrogen getter. It was thought that only absorption of the incorporated boron appeared. In order to confirm this effect, synthesis was attempted by actively adding boron under synthesis conditions in which a relatively large amount of nitrogen remained. As a result, the absorption of Ib-type nitrogen in the ultraviolet (at 4.6 eV) was significantly reduced in the (111) sector having a high boron content.

【０００９】（実験および結果） ホウ素添加によるダイヤモンド合成 Ｆｅ系金属溶媒にＡｌを０．８３原子％添加し、更にホ
ウ素を１５，３０，５０ｐｐｍとそれぞれ変化させて添
加した。温度差法による種結晶にエピタキシャル成長さ
せ、ダイヤモンド単結晶を合成した。合成条件は５．５
ＧＰａで１３５０℃であった。合成に用いた原料はホウ
素を含有しない高純度なものを選択した。このうちホウ
素を３０ｐｐｍ添加して合成した結晶が最も無色透明に
なった為、（１１０）面が観察面になるように研磨し
た。 結晶断面の観察 図３に結晶断面の概略図を示す。図４中に、各セクター
におけるホウ素の含有量および窒素の推定含有量を示
す。ホウ素の含有量はイオン注入法により含有量が判明
している標準資料を予め作成し、ＳＩＭＳにより両者を
比較することで測定した。窒素の含有量は図２のＴｉま
たはＡｌゲッター添加量と結晶中の窒素含有量の関係を
示すグラフ図から推定した。図２において横軸はゲッタ
ーの添加量（原子％）、縦軸は結晶中の窒素量（ｐｐ
ｍ）、○印はＴｉ、△印はＡｌを示す。また、（１１
１）セクターと（１００）セクターにおける紫外可視の
吸収スペクトルを測定した。結果を図４に示す。ホウ素
と窒素が殆ど当モル量含有されている（１１１）セクタ
ーではＩｂ型窒素（at４．６ｅＶ）の吸収が著しく小さ
く、IIa 型の吸収スペクトルになっていることがわか
る。ホウ素が殆ど含有されていない（１００）型セクタ
ーでは、Ｉｂ型の窒素の吸収が現れている。また、赤外
域の吸収では両者ともIIａ型を示した。 考察 前述のようにホウ素と窒素がほぼ当量含まれるセクター
で、孤立分散型で固溶しているＩｂ型窒素の吸収が減少
することから、ＡＤペアーが生じていると推定される。(Experiments and Results) Synthesis of Diamond by Addition of Boron 0.83 atomic% of Al was added to a Fe-based metal solvent, and boron was further added at 15, 30, and 50 ppm, respectively. A single crystal of diamond was synthesized by epitaxially growing a seed crystal by a temperature difference method. The synthesis conditions are 5.5
GPa was 1350 ° C. The raw materials used for the synthesis were selected to be high-purity containing no boron. Of these, the crystal synthesized by adding 30 ppm of boron became the most colorless and transparent, and was polished so that the (110) plane was the observation plane. Observation of crystal cross section FIG. 3 shows a schematic diagram of the crystal cross section. FIG. 4 shows the content of boron and the estimated content of nitrogen in each sector. The boron content was measured by preparing in advance standard data whose content was known by an ion implantation method and comparing the two by SIMS. The nitrogen content was estimated from the graph of FIG. 2 showing the relationship between the amount of Ti or Al getter added and the nitrogen content in the crystal. In FIG. 2, the horizontal axis represents the amount of the getter added (atomic%), and the vertical axis represents the nitrogen content in the crystal (pp
m), ○ indicates Ti, Δ indicates Al. Also, (11
1) UV-visible absorption spectra in the sector and the (100) sector were measured. FIG. 4 shows the results. In the (111) sector containing boron and nitrogen in almost equimolar amounts, the absorption of type Ib nitrogen (at 4.6 eV) is remarkably small, and the absorption spectrum is type IIa. In the (100) type sector, which contains little boron, absorption of type Ib nitrogen appears. In addition, both exhibited IIa type in the absorption in the infrared region. Consideration As described above, in the sector containing boron and nitrogen in substantially equivalent amounts, the absorption of the isolated and dispersed solid solution type Ib-type nitrogen decreases, so it is presumed that an AD pair is generated.

【００１０】本発明においては、ダイヤモンド結晶中に
含まれる窒素およびホウ素の原子数は同程度である程好
ましい。両者の原子数の差が１０17原子／ｃｍ3 以下で
あれば、天然ダイヤモンドや従来の合成Ｉｂ型ダイヤモ
ンドとくらべ、はるかに歪みの少ないダイヤモンドとな
る。すなわち、第一結晶を合成ダイヤモンド結晶（００
４）面平行配置とする二結晶法で測定した場合のＸ線回
折ロッキングカーブの半値幅が１０秒以下、あるいはラ
マン分光スペクトルの１３３２ｃｍ-1のピークの半値幅
が２．３ｃｍ-1以上かの従来にない結晶性のよいダイヤ
モンドが得られる。たとえば天然IIａ型ダイヤモンド、
天然Ｉａ型ダイヤモンド、従来法によるＩｂ型合成ダイ
ヤモンドをそれぞれ７〜１０個用意し、前記と同様にし
て測定したロッキングカーブ半値幅はそれぞれ３００〜
３０００秒、２００〜６００秒、１５〜３０秒であり、
ラマン分光スペクトル１３３２ｃｍ-1ピークの半値幅は
それぞれ、２．１５〜３．５ｃｍ-1、２．８〜３．３ｃ
ｍ-1、２．４〜２．６ｃｍ-1であった。In the present invention, it is preferable that the numbers of atoms of nitrogen and boron contained in the diamond crystal are substantially the same. If the difference in the number of atoms between them is 10 17 atoms / cm 3 or less, the diamond is much less strained than natural diamond or conventional synthetic Ib type diamond. That is, the first crystal is replaced with a synthetic diamond crystal (00
4) surface parallel arrangement to two half-width of X-ray diffraction rocking curve as measured with crystal method is 10 seconds or less, or half width of the peak of the Raman spectrum of 1332 cm -1 is either 2.3 cm -1 or more Unprecedented diamond with good crystallinity can be obtained. For example, natural IIa type diamond,
Seven to ten natural Ia-type diamonds and seven to ten Ib-type synthetic diamonds by a conventional method were prepared, and the rocking curve half-widths measured in the same manner as described above were 300 to 300, respectively.
3000 seconds, 200-600 seconds, 15-30 seconds,
The full width at half maximum of the Raman spectroscopy spectrum 1332 cm -1 peak is 2.15 to 3.5 cm -1 and 2.8 to 3.3 c, respectively.
m −1 , 2.4 to 2.6 cm −1 .

【００１１】さらにダイヤモンド結晶中に含まれる窒素
原子数とホウ素原子数の差が１０16／ｃｍ3 以下のもの
がより好ましく、さらに結晶性が向上する。この場合、
第一結晶を合成ダイヤモンド結晶（００４）面平行配置
とする二結晶法で測定した場合のＸ線ロッキングカーブ
の半値幅が７秒以下、ラマン分光スペクトルの１３３２
ｃｍ-1のピークの半値幅が２ｃｍ-1以下の極めて結晶性
の良いダイヤモンドとなり、モノクロメーターや半導体
基板など、高度な結晶性の要求される用途に充分適用で
きる。しかもこの場合、近紫外域から遠赤外域までダイ
ヤモンド自体の吸収以外、窒素やホウ素等の不純物によ
る光の吸収がなく、各種光学部品や窓材に適用できる。
そして無色でかなり透明度の高いダイヤモンド結晶であ
るため、装飾用途にも適用できる。この場合のダイヤモ
ンド結晶のカラーグレードはＧＩＡスケールで、Ｇカラ
ー以上であり、装飾用ダイヤモンドの評価として最高級
レベルに位置する。なお、従来知られている合成IIａ型
ダイヤモンドは、同様の評価でＨ〜Ｊ程度と中級レベル
のものであった（特開昭５２−８８２８９号公報）事実
と比較すると、本発明のダイヤモンドの優れていること
が明らかに理解されよう。It is more preferable that the difference between the number of nitrogen atoms and the number of boron atoms contained in the diamond crystal is 10 16 / cm 3 or less, and the crystallinity is further improved. in this case,
Synthetic diamond crystal (004) plane parallel to first crystal
The half-width of the X-ray rocking curve measured by the two-crystal method is 7 seconds or less, and the Raman spectrum 1332
The diamond has extremely high crystallinity with a half width at a peak of cm -1 of 2 cm -1 or less, and is sufficiently applicable to applications requiring high crystallinity such as a monochromator and a semiconductor substrate. Moreover, in this case, there is no absorption of light due to impurities such as nitrogen and boron other than the absorption of diamond itself from near-ultraviolet region to far-infrared region.
Since it is a colorless and highly transparent diamond crystal, it can also be used for decorative purposes. The color grade of the diamond crystal in this case is GIA scale, G color or higher, and is positioned at the highest grade as a diamond for decoration. Incidentally, the conventionally known synthetic IIa type diamond was of an intermediate level of about H to J in the same evaluation (Japanese Patent Application Laid-Open No. 52-88289). It will be clearly understood that

【００１２】以上のようなダイヤモンドを合成するに
は、温度差法によるダイヤモンド単結晶の合成方法にお
いて、合成中に結晶内に取り込まれる窒素量とホウ素の
量が、原子数で同程度になるよう、溶媒中に添加する窒
素ゲッターの添加量を調整する、または、炭素源もしく
は溶媒中に添加するホウ素量を調整すればよい。具体的
には例えば次の如くである。 (1) 炭素源や溶媒原料に不純物として含まれるホウ素が
ダイヤモンド結晶中に取り込まれる量と同程度の窒素が
結晶中に残るように窒素ゲッターの添加量を加減する、
(2) ダイヤモンドの結晶成長を阻害しない程度に窒素ゲ
ッターを添加し、このとき取りきれなかった窒素と同程
度のホウ素がダイヤモンド中に取り込まれるように、予
め炭素源もしくは溶媒中にホウ素もしくはホウ素を含む
化合物を添加する、などの方法が挙げられるが、使用す
る炭素源や溶媒の種類（ホウ素含有量）や、使用する窒
素ゲッターの窒素除去効率、結晶成長を阻害する程度な
どを考慮して、それぞれの場合に適した手法を選択すれ
ばよい。In order to synthesize diamond as described above, in a method of synthesizing a single crystal of diamond by a temperature difference method, the amount of nitrogen and the amount of boron incorporated into the crystal during the synthesis are almost the same in terms of the number of atoms. The amount of the nitrogen getter added to the solvent may be adjusted, or the amount of boron added to the carbon source or the solvent may be adjusted. Specifically, for example, it is as follows. (1) the amount of nitrogen getter added or reduced so that the same amount of nitrogen as the amount of boron contained as an impurity in the carbon source or the solvent raw material is taken into the diamond crystal remains in the crystal.
(2) Add a nitrogen getter to the extent that it does not hinder the crystal growth of diamond, and add boron or boron in a carbon source or solvent in advance so that the same amount of boron as nitrogen that could not be removed at this time is incorporated into diamond. The method includes adding a compound containing, for example, the type of the carbon source and the solvent to be used (boron content), the nitrogen removal efficiency of the nitrogen getter to be used, the degree of inhibiting crystal growth, and the like. What is necessary is just to select the method suitable for each case.

【００１３】本発明において溶媒に添加する窒素ゲッタ
ーとしては、Ａｌもしくは、Ｔｉ、Ｚｒ、Ｈｆ、Ｖ、Ｎ
ｂ、ＴａなどのIVａ族元素、Ｖａ族元素を用いることが
できる。IVａ族元素、Ｖａ族元素を窒素ゲッターとする
場合、これら元素の炭化物の生成を抑制する物質を添加
することが好ましい。このような物質としては、例えば
Ａｌ，Ｎｉ，Ｃｕ、Ｚｎ，Ｇａ，Ａｇ，Ｃｄ，Ｉｎ，Ｓ
ｎ，Ａｕ，ＴｌおよびＰｂから選ばれる元素を溶媒金属
に対し０．１〜２０重量％添加することが効果的であ
る。 このような知見のもととなった実験は次のとおり
である。In the present invention, as the nitrogen getter to be added to the solvent, Al or Ti, Zr, Hf, V, N
Group IVa elements such as b and Ta, and Va group elements can be used. When a group IVa element or a group Va element is used as a nitrogen getter, it is preferable to add a substance that suppresses the formation of carbides of these elements. Such materials include, for example, Al, Ni, Cu, Zn, Ga, Ag, Cd, In, S
It is effective to add an element selected from n, Au, Tl and Pb to the solvent metal in an amount of 0.1 to 20% by weight. The experiment that led to such knowledge is as follows.

【００１４】(a) 実験 金属溶媒にＴｉ及びＣｕを添加し、温度差法で圧力５．
５ＧＰａ、温度１３００〜１４００℃で数十時間保持
し、１〜２カラットのダイヤ結晶を育成した。得られた
結晶に含まれる溶媒の巻き込み（メタルインクルージョ
ン）やその他の内包物の含有程度を顕微鏡で観察した。
また、厚み１ｍｍ程度に研磨して紫外吸収スペクトルを
測定し、４．６ｅＶの吸収により窒素量を見積った。 (b) 結果及び考察 Ｔｉを金属溶媒に添加しただけでは内包物が多く、金属
溶媒の巻き込み以外にも十数μｍの不純物が多量に含ま
れ、良質なダイヤモンド結晶は殆ど得られなかった。合
成後の金属溶媒の断面を観察すると、数μｍ〜十数μｍ
の異物が多く見られ、ＥＰＭＡによる分析の結果、この
異物はＴｉＣであることが判った。ダイヤモンド結晶中
の微小不純物はこのＴｉＣがダイヤモンド結晶中に取り
込まれたものと思われる。また、金属溶媒の巻き込みが
多いのは、金属溶媒中に多量のＴｉＣが生成することに
より炭素の供給が阻害されたためと考えられる。Ｔｉを
添加し、更にＣｕを添加した場合、溶媒中に観察される
ＴｉＣは１μｍ以下に小さくなり、量も大幅に減少し、
得られるダイヤモンド結晶中の内包物も低減した。Ｃｕ
添加によりＴｉＣが分解された、もしくはＴｉＣの生成
が抑制されたものと思われる。表１に代表的な合成実験
の結果を示す。Ｔｉ添加量１．５％以上でほぼ完全に窒
素が除去され、Ｃｕを１〜３％添加しても状況は変わら
ない。図５にＴｉ、Ｃｕの添加量を変えて合成したダイ
ヤモンド結晶の紫外吸収スペクトルを示すが、Ｔｉ添加
量１．５％で窒素による吸収は殆ど見られなくなる。ま
た、Ｔｉと同程度のＣｕを添加することにより、溶媒の
巻き込み（メタル）及び微小不純物の混入量が大幅に減
少し、良質なダイヤモンド結晶が安定して得られるよう
になる。なお、表１のメタルインクルージョンの評価
（＋＋、＋、−）の基準を図６に示す。(A) Experiment Ti and Cu are added to a metal solvent, and pressure is determined by a temperature difference method.
The temperature was maintained at 5 GPa and a temperature of 1300 to 1400 ° C. for several tens of hours to grow diamond crystals of 1 to 2 carats. The entrapment of the solvent (metal inclusion) contained in the obtained crystals and the content of other inclusions were observed with a microscope.
Further, polishing was performed to a thickness of about 1 mm to measure an ultraviolet absorption spectrum, and the nitrogen amount was estimated based on an absorption of 4.6 eV. (b) Results and Discussion The addition of Ti to the metal solvent alone resulted in a large amount of inclusions, a large amount of impurities of more than 10 μm in addition to the involvement of the metal solvent, and almost no high-quality diamond crystals were obtained. Observing the cross section of the metal solvent after synthesis, several μm to several tens μm
Many foreign substances were observed, and as a result of analysis by EPMA, the foreign substances were found to be TiC. It is considered that the minute impurities in the diamond crystal were such that TiC was incorporated into the diamond crystal. Further, it is considered that the reason why the entrainment of the metal solvent is large is that the generation of a large amount of TiC in the metal solvent impeded the supply of carbon. When Ti is added and Cu is further added, the TiC observed in the solvent is reduced to 1 μm or less, and the amount is significantly reduced.
Inclusions in the resulting diamond crystals were also reduced. Cu
It seems that TiC was decomposed by the addition, or the production of TiC was suppressed. Table 1 shows the results of typical synthetic experiments. Nitrogen is almost completely removed when the amount of Ti added is 1.5% or more, and the situation does not change even when 1 to 3% of Cu is added. FIG. 5 shows an ultraviolet absorption spectrum of a diamond crystal synthesized by changing the addition amounts of Ti and Cu. When the Ti addition amount is 1.5%, absorption by nitrogen is hardly observed. Further, by adding Cu of the same level as that of Ti, the entrainment of the solvent (metal) and the amount of the minute impurities mixed are greatly reduced, and a high-quality diamond crystal can be stably obtained. FIG. 6 shows the criteria (++, +,-) for metal inclusion evaluation in Table 1.

【００１５】[0015]

【表１】 [Table 1]

【００１６】本発明の製造方法において溶媒金属として
は例えばＦｅ、Ｃｏ、Ｎｉ、Ｍｎ、Ｃｒ等の金属あるい
はこれらの金属からなる合金が挙げられる。本発明の炭
素源としては合成もしくは天然のダイヤモンド粉末また
はグラファイ粉末もくしは成型体が挙げられる。種結晶
としては合成もしくは天然ダイヤモンドの小さな結晶が
挙げられる。また、本発明においてはダイヤモンド合成
時に、種面と溶媒との間に結晶初期の成長状態の安定化
のため、Ａｌ，Ｎｉ，Ｃｕ、Ｚｎ，Ｇａ，Ａｇ，Ｃｄ，
Ｉｎ，Ｓｎ，Ａｕ，ＴｌおよびＰｂから選ばれる元素を
材質とする緩衝材、例えばＡｌ板やＣｕ板などの緩衝材
を配置することが効果的である。緩衝材の板厚は０．０
１〜０．５mm程度でよい。これにより、結晶成長初期の
不安定成長による結晶中の結晶欠陥や歪みを低減させる
ことができる。このような手段を採用することにより、
内包物の混入による歪みや、結晶成長初期の不安定成長
による結晶中の結晶欠陥や歪みを低減させることができ
る。In the production method of the present invention, examples of the solvent metal include metals such as Fe, Co, Ni, Mn, and Cr and alloys composed of these metals. Examples of the carbon source of the present invention include synthetic or natural diamond powder or graphite powder or a molded product. Seed crystals include small crystals of synthetic or natural diamond. In the present invention, at the time of diamond synthesis, Al, Ni, Cu, Zn, Ga, Ag, Cd, and the like are used to stabilize the initial crystal growth state between the seed surface and the solvent.
It is effective to arrange a buffer material made of an element selected from In, Sn, Au, Tl and Pb, for example, a buffer material such as an Al plate or a Cu plate. The thickness of the cushioning material is 0.0
It may be about 1 to 0.5 mm. As a result, crystal defects and distortion in the crystal due to unstable growth at the initial stage of crystal growth can be reduced. By adopting such means,
Distortion due to inclusion inclusions and crystal defects and distortion in the crystal due to unstable growth in the initial stage of crystal growth can be reduced.

【００１７】さらに本発明においては、温度差法による
ダイヤモンド合成の技術分野での一般的な超高圧高温条
件でダイヤモンドを合成させた後試料部の温度および圧
力を常温、常圧下に降温、除圧する際、内部温度が３０
０〜１０００℃の状態で、好ましくは４００〜８００
℃、より好ましくは５００〜６００℃の状態で加圧を解
除するとより効果的であり、結晶に応力による歪みが残
留することを低減できる。Further, in the present invention, after the diamond is synthesized under ultra-high pressure and high temperature conditions generally used in the technical field of diamond synthesis by the temperature difference method, the temperature and pressure of the sample portion are reduced to normal temperature and normal pressure and depressurized. When the internal temperature is 30
0-1000 ° C., preferably 400-800 ° C.
It is more effective to release the pressure at a temperature of 500 ° C., more preferably 500 to 600 ° C., and it is possible to reduce the residual strain due to stress in the crystal.

【００１８】[0018]

〔実施例１〕[Example 1]

図１に本発明実施例でダイヤモンド合成に用いた試料室
構成を示す。ここで、炭素源(1) にＢ（ホウ素）含有量
が１１ｐｐｍの合成ダイヤモンド粉末を用いた。溶媒金
属(2) にはＢ含有量２ｐｐｍのＦｅ、Ｃｏを用い、溶媒
金属組成はＦｅ／Ｃｏ＝６０／４０（重量比）とした。
この溶媒金属に、窒素ゲッターとしてＴｉを０．８重量
％添加し、同時にＣｕを１重量％添加した。種結晶(3)
には５００μｍサイズのダイヤモンド結晶を用いた。そ
して、炭素源(1) と種結晶(3）間に約３０℃の温度差が
つくよう加熱用黒鉛ヒーター(5) 内にセットした。これ
を、超高圧発生装置を用いて、圧力５．５ＧＰａ、温度
１３００℃で７０時間保持して種結晶上にダイヤモンド
を育成し、先ず温度を室温にまで下ろし、次いで減圧を
行い、合成したダイヤモンドを取り出した。その結果
０．７〜０．９カラットのIIａ型ダイヤモンド結晶が得
られた。ＳＩＭＳによりダイヤモンド中の窒素とホウ素
を定量分析した結果、それぞれ１．５×１０17原子／ｃ
ｍ3 、１．２×１０17原子／ｃｍ3 であった。得られた
ダイヤモンドについて偏光透過顕微鏡で偏向光透過像を
観察し、歪みを評価した結果、結晶内の歪みがかなり少
ないことが判った。第一結晶を合成ダイヤモンド結晶
（００４）面平行配置とする二結晶法によるＸ線回折の
ロッキングカーブの半値幅を測定したところ、７．０秒
であった。また、ダブルモノクロメーターラマン分光装
置でラマン分光スペクトルを測定し、１３３２ｃｍ-1の
半値幅を求めたところ、２．２ｃｍ-1であった。FIG. 1 shows the configuration of a sample chamber used for diamond synthesis in the embodiment of the present invention. Here, a synthetic diamond powder having a B (boron) content of 11 ppm was used as the carbon source (1). As the solvent metal (2), Fe and Co having a B content of 2 ppm were used, and the solvent metal composition was Fe / Co = 60/40 (weight ratio).
To this solvent metal, 0.8% by weight of Ti was added as a nitrogen getter, and 1% by weight of Cu was simultaneously added. Seed crystal (3)
Used a diamond crystal having a size of 500 μm. Then, it was set in a heating graphite heater (5) so that a temperature difference of about 30 ° C. was obtained between the carbon source (1) and the seed crystal (3). Using an ultra-high pressure generator, the diamond is grown on the seed crystal while maintaining the pressure at 5.5 GPa and the temperature of 1300 ° C. for 70 hours, first lowering the temperature to room temperature, and then reducing the pressure to obtain a synthesized diamond. Was taken out. As a result, a 0.7-0.9 carat type IIa diamond crystal was obtained. As a result of quantitative analysis of nitrogen and boron in diamond by SIMS, 1.5 × 10 17 atoms / c
m 3 and 1.2 × 10 17 atoms / cm 3 . Observation of a polarized light transmission image of the obtained diamond with a polarization transmission microscope and evaluation of distortion revealed that distortion in the crystal was considerably small. When the half width of the rocking curve of the X-ray diffraction by the two crystal method in which the first crystal was arranged in parallel with the synthetic diamond crystal (004) plane was 7.0 seconds. Further, to measure the Raman spectrum in a double monochromator Raman spectroscopic device, was determined the half width of 1332 cm -1, it was 2.2 cm -1.

【００１９】〔実施例２〕 Ｔｉ添加量１．５重量％、Ｃｕ添加量１．５重量％とし
た他は実施例１と同様にダイヤモンドを合成した。得ら
れたダイヤモンドはやや青みがかった結晶で、ＳＩＭＳ
による分析では窒素量は１．０×１０16ｐｐｍ原子／ｃ
ｍ-1、ホウ素は１．２×１０17原子／ｃｍ-1であった。
赤外吸収スペクトルを測定すると、２８００ｃｍ-1付近
にホウ素による吸収が認められた。得られたダイヤモン
ドについて偏光顕微鏡で偏向光透過像を観察し、歪みを
評価した結果、結晶内の歪みが少ないことが判った。ま
た、第一結晶を合成ダイヤモンド結晶（００４）面平行
配置とする二結晶法によるＸ線回折のロッキングカーブ
の半値幅を測定したところ、８．３秒であった。また、
ダブルモノクロメーターラマン分光装置でラマン分光ス
ペクトルを測定し、１３３２ｃｍ-1の半値幅を求めたと
ころ、２．５ｃｍ-1であった。Example 2 Diamond was synthesized in the same manner as in Example 1 except that the amount of Ti was 1.5% by weight and the amount of Cu was 1.5% by weight. The resulting diamond is a slightly bluish crystal, SIMS
Analysis revealed that the nitrogen content was 1.0 × 10 16 ppm atoms / c.
m -1 and boron were 1.2 × 10 17 atoms / cm -1 .
When the infrared absorption spectrum was measured, absorption by boron was observed at around 2800 cm -1 . Observation of a polarized light transmission image of the obtained diamond with a polarizing microscope and evaluation of distortion revealed that distortion in the crystal was small. In addition, the first crystal is a synthetic diamond crystal (004) plane parallel.
It was 8.3 seconds when the half width of the rocking curve of the X-ray diffraction by the two-crystal method was measured. Also,
The Raman spectrum was measured with a double monochromator Raman spectroscopic device, was determined the half width of 1332 cm -1, it was 2.5 cm -1.

【００２０】〔実施例３〕 炭素源に対し０．０．４重量％（炭素源に対し）のホウ
素を添加し、窒素ゲッターとしてＡｌを１．５重量％添
加し、Ｃｕを添加しなかった他は実施例１と同様にして
ダイヤモンドを合成した。その結果、０．７〜０．９カ
ラットのIIａ型ダイヤモンド結晶が得られた。ＳＩＭＳ
によりダイヤモンド中の窒素とホウ素を定量分析した結
果、それぞれ１．８×１０17原子／ｃｍ3 、１．５×１
０17原子／ｃｍ3 であった。得られたダイヤモンドにつ
いて偏光透過顕微鏡により偏向光透過像を観察し、歪み
を評価した結果、結晶内の歪みがかなり少ないことが判
った。また、第一結晶を合成ダイヤモンド結晶（００
４）面平行配置とする二結晶法によるＸ線回折のロッキ
ングカーブの半値幅を測定したところ、７．２秒であっ
た。また、ダブルモノクロメーターラマン分光装置でラ
マン分光スペクトルを測定し、１３３２ｃｍ-1の半値幅
を求めたところ、２．２ｃｍ-1であった。Example 3 0.00.4% by weight (based on carbon source) of boron was added to a carbon source, 1.5% by weight of Al was added as a nitrogen getter, and Cu was not added. Others were the same as in Example 1 to synthesize diamond. As a result, a 0.7-0.9 carat type IIa diamond crystal was obtained. SIMS
As a result of quantitative analysis of nitrogen and boron in diamond, 1.8 × 10 17 atoms / cm 3 and 1.5 × 1
It was 0 17 atoms / cm 3 . Observation of a polarized light transmission image of the obtained diamond with a polarized light transmission microscope and evaluation of distortion revealed that distortion in the crystal was considerably small. The first crystal is a synthetic diamond crystal (00
4) The half-width of the rocking curve of the X-ray diffraction by the two-crystal method with the plane parallel arrangement was measured and found to be 7.2 seconds. Further, to measure the Raman spectrum in a double monochromator Raman spectroscopic device, was determined the half width of 1332 cm -1, it was 2.2 cm -1.

【００２１】〔実施例４〕 Ａｌ添加量を０．５重量％とした他は実施例３と同様に
ダイヤモンドを合成した。得られたダイヤモンドはやや
黄色みがかった結晶で、ＳＩＭＳによる分析では窒素量
は１．６×１０16ｐｐｍ原子／ｃｍ-1、ホウ素は１．５
×１０17原子／ｃｍ-1であった。得られたダイヤモンド
について赤外吸収スペクトル、紫外可視スペクトルを測
定すると、いずれも窒素の吸収が認められた。しかし偏
光顕微鏡で偏向光透過像を観察し、歪みを評価した結
果、結晶内の歪みは比較的少ないことが判った。また、
第一結晶を合成ダイヤモンド結晶（００４）面平行配置
とする二結晶法によるＸ線回折のロッキングカーブの半
値幅を測定したところ、８．５秒であった。また、ダブ
ルモノクロメーターラマン分光装置でラマン分光スペク
トルを測定し、１３３２ｃｍ-1の半値幅を求めたとこ
ろ、２．５ｃｍ-1であった。Example 4 Diamond was synthesized in the same manner as in Example 3 except that the amount of Al added was 0.5% by weight. The obtained diamond was a slightly yellowish crystal. According to analysis by SIMS, the amount of nitrogen was 1.6 × 10 16 ppm atom / cm −1 and the amount of boron was 1.5.
× 10 17 atoms / cm -1 . When the infrared absorption spectrum and the ultraviolet-visible spectrum of the obtained diamond were measured, nitrogen absorption was recognized in each case. However, as a result of observing a polarized light transmission image with a polarizing microscope and evaluating distortion, it was found that distortion in the crystal was relatively small. Also,
Synthetic diamond crystal (004) plane parallel to first crystal
When the half width of the rocking curve of the X-ray diffraction by the two crystal method was measured, it was 8.5 seconds. Further, to measure the Raman spectrum in a double monochromator Raman spectroscopic device, was determined the half width of 1332 cm -1, it was 2.5 cm -1.

【００２２】〔実施例５〕 炭素源(1) にＢ（ホウ素）含有量が７ｐｐｍの合成ダイ
ヤモンド粉末を用いた。溶媒金属(2) にはＢ含有量１ｐ
ｐｍのＦｅ、Ｃｏを用い、溶媒金属組成はＦｅ／Ｃｏ＝
６０／４０（重量比）とした。この溶媒金属に窒素ゲッ
ターとしてＴｉを１．５重量％添加し、同時にＣｕを
１．５重量％添加した。その他は実施例１と同様にして
IIａ型ダイヤモンドを合成した。その結果、０．７〜
０．９カラットの無色透明で良質なIIａ型ダイヤモンド
結晶が得られた。ＳＩＭＳによりダイヤモンド中の窒素
とホウ素を定量分析した結果、それぞれ１．１×１０16
原子／ｃｍ3 、１．８×１０16原子／ｃｍ3 であった。
得られたダイヤモンドについて偏光透過顕微鏡により偏
向光透過像を観察し、歪みを評価した結果、結晶内の歪
みは殆ど認められなかった。また、第一結晶を合成ダイ
ヤモンド結晶（００４）面平行配置とする二結晶法によ
るＸ線回折のロッキングカーブの半値幅を測定したとこ
ろ、５．８秒であった。また、ダブルモノクロメーター
ラマン分光装置でラマン分光スペクトルを測定し、１３
３２ｃｍ-1の半値幅を求めたところ、１．８ｃｍ-1であ
った。以上のように、極めて結晶性に優れたダイヤモン
ド結晶であることが判った。また、紫外可視スペクトル
および赤外スペクトルを測定した結果、窒素やホウ素な
どの不純物による光の吸収がまったく見られなかった。
ＧＩＡスケールに基づいて宝石ダイヤモンドとしてのカ
ラーグレードを専門家が評価したところＦカラーであ
り、天然高純度ダイヤモンドの最高級品に相当するグレ
ードのものであった。Example 5 A synthetic diamond powder having a B (boron) content of 7 ppm was used as the carbon source (1). Solvent metal (2) has a B content of 1p
pm Fe, Co, and the solvent metal composition was Fe / Co =
60/40 (weight ratio). To this solvent metal, 1.5% by weight of Ti was added as a nitrogen getter, and 1.5% by weight of Cu was simultaneously added. Others are the same as in Example 1.
IIa type diamond was synthesized. As a result, 0.7-
0.9 carats of colorless, transparent and good quality IIa diamond crystals were obtained. As a result of quantitative analysis of nitrogen and boron in diamond by SIMS, 1.1 × 10 16
Atoms / cm 3 , 1.8 × 10 16 atoms / cm 3 .
As a result of observing a polarized light transmission image of the obtained diamond with a polarization transmission microscope and evaluating the distortion, almost no distortion in the crystal was recognized. The half width of the rocking curve of the X-ray diffraction by the two-crystal method in which the first crystal was arranged in parallel with the synthetic diamond crystal (004) plane was 5.8 seconds. The Raman spectrum was measured with a double monochromator Raman spectrometer,
When the half width of 32 cm -1 was determined, it was 1.8 cm -1 . As described above, it was found that the diamond crystal was extremely excellent in crystallinity. In addition, as a result of measuring an ultraviolet-visible spectrum and an infrared spectrum, no light absorption by impurities such as nitrogen and boron was observed.
Experts evaluated the color grade as a gem diamond based on the GIA scale and found that it was F color, a grade corresponding to the highest grade natural high purity diamond.

【００２３】〔実施例６〕溶媒金属と種結晶の間に、初
期の結晶成長の安定化のための緩衝材として、厚み０．
０５ｍｍのＡｌ板を配置した他は実施例５と同様にして
IIａ型ダイヤモンドを作成した。その結果、ロッキング
カーブ半値幅は５．７秒、ラマン分光スペクトルピーク
の半値幅は１．６ｃｍ-1で結晶性がさらに改良された。
その他の特性は実施例５と同様であった。[Embodiment 6] Between a solvent metal and a seed crystal, as a buffer material for stabilizing initial crystal growth, a thickness of 0.1 mm is used.
Except that an Al plate of 05 mm was arranged, the same as in Example 5
IIa type diamond was prepared. As a result, the half-width of the rocking curve was 5.7 seconds, and the half-width of the peak of the Raman spectrum was 1.6 cm -1 , which further improved the crystallinity.
Other characteristics were the same as in Example 5.

【００２４】〔実施例７〕ダイヤモンドを合成後、降
温、減圧を同時に行い、内部温度が５００℃の状態で、
除圧を完了するようにした他は、実施例５と同様にして
IIａ型ダイヤモンドを作成した。その結果、ロッキング
カーブ半値幅は５．７秒、ラマン分光スペクトルピーク
の半値幅は１．６ｃｍ-1で、結晶性が改良された。その
他の特性は実施例５と同様であった。Example 7 After synthesizing diamond, the temperature was reduced and the pressure was reduced at the same time.
Except for completing the depressurization, the same as in Example 5
IIa type diamond was prepared. As a result, the FWHM of the rocking curve was 5.7 seconds, and the FWHM of the peak of the Raman spectrum was 1.6 cm −1 , and the crystallinity was improved. Other characteristics were the same as in Example 5.

【００２５】[0025]

【発明の効果】以上の説明および実施例の結果から明ら
かなように、本発明による合成ダイヤモンド単結晶は窒
素およびホウ素を不純物として含むものの、両者の含有
量が同程度で、お互いに補償しあっているため、不純物
を殆ど含まない高純度IIａ型ダイヤモンドと同様に窒素
やホウ素による光の吸収がなく、また結晶中の歪みが少
ない。そのため、加工中の割れや亀裂などの不具合が少
なくなり、また、超高圧発生用ダイヤモンドアンビル、
ＦＴ−ＩＲ用ダイヤモンドアンビルとして用いた場合、
その寿命や安定性が大幅に向上する。さらに、極めて高
度な結晶性や光透過特性を有するダイヤモンドの合成も
可能であるため、モノクロメーターや半導体基板、装飾
用途にも適用できる。また一方、従来は窒素およびホウ
素を完全に除去することは極めて困難であったが、本発
明の製造方法によればダイヤモンド結晶中の中に窒素や
ホウ素がある程度残留する状態でも窒素ゲッター添加量
やホウ素添加量を加減するという簡単な手法により、天
然高純度IIａ型ダイヤモンドと同程度の光透過特性や結
晶性を有するダイヤモンド単結晶が容易に合成できるの
で、本発明は産業上非常に有利である。As is clear from the above description and the results of the examples, although the synthetic diamond single crystal according to the present invention contains nitrogen and boron as impurities, the contents of both are almost the same, and they are mutually compensated. Therefore, as in the case of high-purity type IIa diamond containing almost no impurities, there is no absorption of light by nitrogen or boron, and there is little distortion in the crystal. For this reason, defects such as cracks and cracks during processing are reduced, and a diamond anvil for generating ultra-high pressure,
When used as a diamond anvil for FT-IR,
Its life and stability are greatly improved. Furthermore, since it is possible to synthesize diamond having extremely high crystallinity and light transmission characteristics, it can be applied to monochromators, semiconductor substrates, and decorative applications. On the other hand, conventionally, it has been extremely difficult to completely remove nitrogen and boron. However, according to the production method of the present invention, even when nitrogen and boron remain to some extent in the diamond crystal, the amount of nitrogen getter added and The present invention is very industrially advantageous because a simple method of adjusting the amount of boron added can easily synthesize a diamond single crystal having the same light transmission characteristics and crystallinity as natural high-purity type IIa diamond. .

【図面の簡単な説明】[Brief description of the drawings]

【図１】は本発明のダイヤモンド合成における試料室の
構成の概略説明図である。FIG. 1 is a schematic explanatory view of the configuration of a sample chamber in diamond synthesis according to the present invention.

【図２】はＴｉまたはＡｌゲッター添加量と結晶中の窒
素含有量の関係を示すグラフ図である。FIG. 2 is a graph showing the relationship between the amount of Ti or Al getter added and the nitrogen content in the crystal.

【図３】は結晶断面の概略説明図である。FIG. 3 is a schematic explanatory view of a crystal cross section.

【図４】は（１１１）セクターと（１００）セクターに
おけるホウ素の含有量および窒素の推定含有量と各セク
ターにおける紫外可視の吸収スペクトルを示した図であ
る。FIG. 4 is a diagram showing the boron content and the estimated nitrogen content in the (111) sector and the (100) sector, and the ultraviolet-visible absorption spectrum in each sector.

【図５】はＴｉ、Ｃｕの添加量を変えて合成したダイヤ
モンド結晶の紫外吸収スペクトル図である。FIG. 5 is an ultraviolet absorption spectrum diagram of a diamond crystal synthesized by changing the addition amounts of Ti and Cu.

【図６】は表１のメタルインクルージョンの評価（＋
＋、＋、−）の基準を示す説明図である。FIG. 6 shows the evaluation of metal inclusion in Table 1 (+
It is explanatory drawing which shows the reference | standard of +, +,-).

【符号の説明】[Explanation of symbols]

１ 炭素源 ２ 溶媒金属 ３ 種結晶 ４ 絶縁体 ５ 黒鉛ヒーター ６ 圧力媒体 DESCRIPTION OF SYMBOLS 1 Carbon source 2 Solvent metal 3 Seed crystal 4 Insulator 5 Graphite heater 6 Pressure medium

───────────────────────────────────────────────────── フロントページの続き (56)参考文献 特開 昭52−88289（ＪＰ，Ａ) 特開 昭58−161995（ＪＰ，Ａ) 特開 平４−266020（ＪＰ，Ａ) (58)調査した分野(Int.Cl.7，ＤＢ名) B01J 3/06 C01B 31/06 C30B 29/04 ──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-52-88289 (JP, A) JP-A-58-161995 (JP, A) JP-A-4-266020 (JP, A) (58) Field (Int.Cl. 7 , DB name) B01J 3/06 C01B 31/06 C30B 29/04

Claims (15)

(57)【特許請求の範囲】(57) [Claims] 【請求項１】 結晶中に窒素原子およびホウ素原子を含
有し、該窒素原子数と該ホウ素原子数がほぼ同じ程度
で、且つ前記窒素原子数と前記ホウ素原子数との差が１
×１０17原子／ｃｍ3 以下であることを特徴とする合成
ダイヤモンド単結晶。1. A crystal containing a nitrogen atom and a boron atom, wherein the number of the nitrogen atoms and the number of the boron atoms are substantially the same, and the difference between the number of the nitrogen atoms and the number of the boron atoms is 1
× 10 17 atoms / cm 3 or less, a synthetic diamond single crystal characterized by the following: 【請求項２】 第一結晶を合成ダイヤモンド結晶（００
４）面平行配置とする二結晶法で測定した場合のＸ線回
折ロッキングカーブの半値幅が１０秒以下であることを
特徴とする請求項１記載の合成ダイヤモンド単結晶。2. The method according to claim 1, wherein the first crystal is a synthetic diamond crystal (00).
4) The synthetic diamond single crystal according to claim 1, wherein a half-width of an X-ray diffraction rocking curve measured by a two-crystal method with plane parallel arrangement is 10 seconds or less. 【請求項３】 ラマン分光スペクトルの１３３２ｃｍ-1
のピークの半値幅が２．３ｃｍ-1以下であることを特徴
とする請求項１または請求項２に記載の合成ダイヤモン
ド単結晶。3. The Raman spectrum of 1332 cm -1
3. The synthetic diamond single crystal according to claim 1, wherein the half width of the peak of (b) is 2.3 cm −1 or less. 4. 【請求項４】 結晶中に窒素原子およびホウ素原子を含
有し、該窒素原子数と該ホウ素原子数がほぼ同じ程度
で、且つ前記窒素原子数と前記ホウ素原子数との差が１
×１０16原子／ｃｍ3 以下であることを特徴とする合成
ダイヤモンド単結晶。4. The crystal contains a nitrogen atom and a boron atom, and the number of the nitrogen atoms and the number of the boron atoms are substantially the same.
And the difference between the number of nitrogen atoms and the number of boron atoms is 1
× 10 16 atoms / cm 3 or less, a synthetic diamond single crystal characterized by the following: 【請求項５】 近紫外域から遠赤外域まで窒素またはホ
ウ素による光の吸収がないことを特徴とする請求項４記
載の合成ダイヤモンド単結晶。5. The synthetic diamond single crystal according to claim 4, wherein no light is absorbed by nitrogen or boron from the near ultraviolet region to the far infrared region. 【請求項６】 ＧＩＡカラースケールでＧカラー以上で
ある請求項４または請求項５に記載の合成ダイヤモンド
単結晶。6. The synthetic diamond according to claim 4, which has a G color or higher on a GIA color scale.
Single crystal . 【請求項７】 第一結晶を合成ダイヤモンド結晶（００
４）面平行配置とする二結晶法で測定した場合のＸ線回
折ロッキングカーブの半値幅が７秒以下であることを特
徴とする請求項４ないし請求項６のいずれかに記載の合
成ダイヤモンド単結晶。7. The first crystal is a synthetic diamond crystal (00
4) The synthetic diamond single according to any one of claims 4 to 6, wherein a half-width of an X-ray diffraction rocking curve measured by a two-crystal method in a plane-parallel arrangement is 7 seconds or less. Crystal . 【請求項８】 ラマン分光スペクトルの１３３２ｃｍ-1
のピークの半値幅が２ｃｍ-1以下であることを特徴とす
る請求項４ないし請求項７のいずれかに記載の合成ダイ
ヤモンド単結晶。8. Raman spectrum 1332 cm -1
The synthetic diamond single crystal according to any one of claims 4 to 7, wherein a half-value width of a peak of is 2 cm -1 or less. 【請求項９】 温度差法による超高温高圧下でのダイヤ
モンド単結晶の合成方法において、合成中に結晶内に取
り込まれる窒素量とホウ素量が原子数で同程度になるよ
う、溶媒金属中に添加する窒素ゲッターの添加量を調整
する、または炭素源もしくは溶媒金属中に添加するホウ
素の添加量を調整することを特徴とする請求項１ないし
請求項８のいずれかに記載の合成ダイヤモンド単結晶の
製造方法。9. A method of synthesizing diamond <br/> Mondo single crystals at very high pressure and temperature by the temperature gradient method, the nitrogen content and boron content to be incorporated into the crystal becomes the same extent the atomic during synthesis 9. The method according to claim 1, wherein the amount of nitrogen getter added to the solvent metal is adjusted, or the amount of boron added to the carbon source or the solvent metal is adjusted. A method for producing the synthetic diamond single crystal according to the above. 【請求項１０】 上記窒素ゲッターとしてＡｌを用いる
ことを特徴とする請求項９記載の合成ダイヤモンド単結
晶の製造方法。10. The synthetic diamond single bond according to claim 9, wherein Al is used as said nitrogen getter.
Method for manufacturing crystals . 【請求項１１】 上記窒素ゲッターとして周期律表のIV
ａ族およびＶａ族元素から選ばれる少なくとも１種以上
を用いることを特徴とする請求項９または請求項１０に
記載の合成ダイヤモンド単結晶の製造方法。11. The periodic table as the nitrogen getter
The method for producing a synthetic diamond single crystal according to claim 9 or 10, wherein at least one or more elements selected from group a and group Va elements are used. 【請求項１２】 上記溶媒金属中に周期律表のIVａ族お
よび／またはＶａ族元素の炭化物の生成を抑制する物質
を添加することを特徴とする請求項９ないし請求項１１
のいずれかに記載の合成ダイヤモンド単結晶の製造方
法。12. The solvent metal according to claim 9, wherein a substance that suppresses the formation of carbides of elements of Group IVa and / or Va of the periodic table is added to the solvent metal.
The method for producing a synthetic diamond single crystal according to any one of the above. 【請求項１３】 上記溶媒金属と種面との間に結晶初期
の成長状態の安定化のための緩衝材を配することを特徴
とする請求項９ないし請求項１２のいずれかに記載の合
成ダイヤモンド単結晶の製造方法。13. The synthesis according to claim 9, wherein a buffer material for stabilizing the initial growth state of the crystal is disposed between the solvent metal and the seed surface. A method for producing a diamond single crystal . 【請求項１４】 上記緩衝材がＡｌ，Ｎｉ，Ｃｕ、Ｚ
ｎ，Ｇａ，Ａｇ，Ｃｄ，Ｉｎ，Ｓｎ，Ａｕ，Ｔｌおよび
Ｐｂから選ばれる少なくとも１種以上の元素であること
を特徴とする請求項１３記載の合成ダイヤモンド単結晶
の製造方法。14. The cushioning material is made of Al, Ni, Cu, Z
The method for producing a synthetic diamond single crystal according to claim 13, characterized in that it is at least one element selected from n, Ga, Ag, Cd, In, Sn, Au, Tl and Pb. 【請求項１５】 温度差法により超高圧高温下でダイヤ
モンド単結晶を合成した後に、試料部の温度および圧力
を常温常圧に降温、除圧する際に、該試料部の温度が３
００〜１０００℃の状態で除圧を完了することを特徴と
する請求項９ないし請求項１４のいずれかに記載の合成
ダイヤモンド単結晶の製造方法。15. After synthesizing a diamond single crystal under ultra-high pressure and high temperature by a temperature difference method, when the temperature and pressure of the sample part are lowered to normal temperature and normal pressure and depressurized, the temperature of the sample part becomes 3%.
The method for producing a synthetic diamond single crystal according to any one of claims 9 to 14, wherein the pressure reduction is completed at a temperature of 00 to 1000 ° C.
JP26904093A 1993-10-08 1993-10-27 Synthetic diamond single crystal and method for producing the same Expired - Lifetime JP3339137B2 (en)

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JP26904093A JP3339137B2 (en) 1993-10-27 1993-10-27 Synthetic diamond single crystal and method for producing the same
KR1019940025640A KR100269924B1 (en) 1993-10-08 1994-10-07 A synthetic diamond and process for producing the same
EP94307418A EP0647590B1 (en) 1993-10-08 1994-10-10 A synthetic diamond and a process for the production of the same
DE69411244T DE69411244T2 (en) 1993-10-08 1994-10-10 Synthetic diamond and process for its manufacture
US08/684,725 US6030595A (en) 1993-10-08 1996-07-22 Process for the production of synthetic diamond

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JPH11300194A (en) * 1998-04-23 1999-11-02 Sumitomo Electric Ind Ltd Superhigh pressure generating diamond anvil
EP1671726B1 (en) 2003-10-10 2013-02-13 Sumitomo Electric Industries, Ltd. Diamond tool
KR100644929B1 (en) * 2004-03-04 2006-11-13 한국원자력연구소 Method for preparing the colored diamond by ion implantation and heat treatment
JP6232817B2 (en) * 2013-08-05 2017-11-22 住友電気工業株式会社 Nano-polycrystalline diamond and tool comprising the same
WO2022210934A1 (en) 2021-03-31 2022-10-06 住友電気工業株式会社 Single-crystal diamond and production method therefor
JPWO2022210566A1 (en) 2021-03-31 2022-10-06
WO2022210935A1 (en) 2021-03-31 2022-10-06 住友電気工業株式会社 Single crystal diamond and method for producing same
EP4317542A1 (en) 2021-03-31 2024-02-07 Sumitomo Electric Industries, Ltd. Single crystal diamond and method for producing same
EP4317544A1 (en) 2021-03-31 2024-02-07 Sumitomo Electric Industries, Ltd. Single-crystal diamond and diamond composite comprising same
EP4317540A1 (en) 2021-03-31 2024-02-07 Sumitomo Electric Industries, Ltd. Single crystal diamond and method for producing same

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