JPH01215799A - Semi-insulating gaas compound semiconductor single crystal and production thereof - Google Patents
Semi-insulating gaas compound semiconductor single crystal and production thereofInfo
- Publication number
- JPH01215799A JPH01215799A JP4250688A JP4250688A JPH01215799A JP H01215799 A JPH01215799 A JP H01215799A JP 4250688 A JP4250688 A JP 4250688A JP 4250688 A JP4250688 A JP 4250688A JP H01215799 A JPH01215799 A JP H01215799A
- Authority
- JP
- Japan
- Prior art keywords
- crystal
- concentration
- single crystal
- semi
- gaas
- 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.)
- Granted
Links
- 239000013078 crystal Substances 0.000 title claims abstract description 73
- 239000004065 semiconductor Substances 0.000 title claims abstract description 10
- 238000004519 manufacturing process Methods 0.000 title claims description 10
- 150000001875 compounds Chemical class 0.000 title description 2
- 229910001218 Gallium arsenide Inorganic materials 0.000 claims abstract description 36
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 27
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 24
- 239000012535 impurity Substances 0.000 claims abstract description 18
- -1 GaAs compound Chemical class 0.000 claims abstract description 10
- 230000007547 defect Effects 0.000 claims abstract description 5
- 238000000034 method Methods 0.000 abstract description 43
- 239000002994 raw material Substances 0.000 abstract description 5
- 229910052785 arsenic Inorganic materials 0.000 abstract description 3
- 229910052733 gallium Inorganic materials 0.000 abstract description 3
- 229910052790 beryllium Inorganic materials 0.000 abstract description 2
- 229910052793 cadmium Inorganic materials 0.000 abstract description 2
- 229910052749 magnesium Inorganic materials 0.000 abstract description 2
- 239000007788 liquid Substances 0.000 abstract 1
- 239000011369 resultant mixture Substances 0.000 abstract 1
- 229910052725 zinc Inorganic materials 0.000 abstract 1
- 239000000370 acceptor Substances 0.000 description 13
- 235000012431 wafers Nutrition 0.000 description 13
- 238000005259 measurement Methods 0.000 description 6
- 238000007796 conventional method Methods 0.000 description 4
- 239000000758 substrate Substances 0.000 description 4
- 239000000203 mixture Substances 0.000 description 3
- 238000005204 segregation Methods 0.000 description 3
- 238000005033 Fourier transform infrared spectroscopy Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000005468 ion implantation Methods 0.000 description 2
- 229910052748 manganese Inorganic materials 0.000 description 2
- 239000000155 melt Substances 0.000 description 2
- 239000010453 quartz Substances 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- 229910052709 silver Inorganic materials 0.000 description 2
- 229910018885 Pt—Au Inorganic materials 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 230000001133 acceleration Effects 0.000 description 1
- 230000004913 activation Effects 0.000 description 1
- 239000003708 ampul Substances 0.000 description 1
- 238000000137 annealing Methods 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 238000002513 implantation Methods 0.000 description 1
- 239000012774 insulation material Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 238000005498 polishing Methods 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 239000000565 sealant Substances 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 238000010583 slow cooling Methods 0.000 description 1
- 230000002269 spontaneous effect Effects 0.000 description 1
- 238000003786 synthesis reaction Methods 0.000 description 1
- 229910052726 zirconium Inorganic materials 0.000 description 1
Landscapes
- Crystals, And After-Treatments Of Crystals (AREA)
- Liquid Deposition Of Substances Of Which Semiconductor Devices Are Composed (AREA)
Abstract
Description
【発明の詳細な説明】
［産業上の利用分野］
本発明は半絶縁性のＧａＡｓ化合物半導体単結晶及びそ
の製造方法に関するもので、特に不純物としてＺｎ等を
添加してＧａＡｓ化合物半導体の半絶縁性化を図る技術
に関する。Detailed Description of the Invention [Industrial Application Field] The present invention relates to a semi-insulating GaAs compound semiconductor single crystal and a method for manufacturing the same, and in particular, the invention relates to a semi-insulating GaAs compound semiconductor single crystal and a method for manufacturing the same, and in particular, to improve the semi-insulating property of a GaAs compound semiconductor by adding Zn or the like as an impurity. Concerning technology for achieving
［従来の技術］
化合物半導体単結晶を製造する方法としては、当該結晶
の融液に種結晶を浸漬してこれを徐々に引き上げて単結
晶を育成する方法や、あるいは、当該結晶の融液を徐々
に冷却固化させ単結晶を育成する方法がある。特に、Ｇ
ａＡｓ単結晶は前者に属する液体封止チョクラルスキー
法（ＬＥＣ法）や、後者に属する徐冷法（ＧＦ法）、水
平ブリッジマン法（ＨＢ法）、垂直ブリッジマン法（Ｖ
Ｂ法）で育成されている。[Prior Art] Methods for producing a compound semiconductor single crystal include a method in which a seed crystal is immersed in a melt of the crystal and gradually pulled up to grow a single crystal; There is a method of gradually cooling and solidifying to grow a single crystal. In particular, G
aAs single crystals can be produced using the liquid-enclosed Czochralski method (LEC method), which belongs to the former, slow cooling method (GF method), horizontal Bridgman method (HB method), and vertical Bridgman method (V method), which belongs to the latter.
B method).
通常、ＧａＡｓＦＥＴやＧａＡｓ ＩＣには半絶縁性の
Ｇ ａ Ａ ｓ単結晶の基板が用いられる。この半絶縁
性Ｇ ａ Ａ ｓ基板としては、アンドープＧａＡｓや
ＣｒドープＧａＡｓが工業的に製造されており、ＨＢ法
がＣｒドープＧａＡｓの製造に、また、ＬＥＣ法がアン
ドープＧａＡｓやＣｒドープＧ ａ Ａ ｓの製造に使
用されている。Usually, a semi-insulating GaAs single crystal substrate is used for GaAsFETs and GaAs ICs. Undoped GaAs and Cr-doped GaAs are industrially produced as semi-insulating GaAs substrates, and the HB method is used to produce Cr-doped GaAs, and the LEC method is used to produce undoped GaAs and Cr-doped GaAs. It is used in the production of s.
ＨＢ法およびＬＥＣ法のいずれの場合についても、Ｇａ
Ａｓは禁制帯幅が１．４ｅＶで、不純物を全く含まなけ
れば真性キャリア濃度が１．８×１０’ａｍ−’で半絶
縁性となる。しかし、現在の技術では、いかに純度を高
めようとしてもシャロードナーとなるＳｉやシャローア
クセプターとなる炭素などが一定量残存し、半絶縁性と
はなりえない。ＧａＡｓが半絶縁性となるのはこのよう
なシャロードナーやシャローアクセプターがディープド
ナーとなるＥＬ２やディープアクセプターとなるＣｒに
よって補償されるためである。In both the HB method and LEC method, Ga
As has a forbidden band width of 1.4 eV, and if it does not contain any impurities, it has an intrinsic carrier concentration of 1.8×10'am-' and is semi-insulating. However, with current technology, no matter how much purity is attempted, a certain amount of Si, which acts as a shallow donor, and carbon, which acts as a shallow acceptor, remain, making it impossible to achieve semi-insulating properties. The reason why GaAs is semi-insulating is that such shallow donors and shallow acceptors are compensated by EL2, which is a deep donor, and Cr, which is a deep acceptor.
ＨＢ法では通常石英アンプルを用いて結晶を育成するた
め１石英からのＳｉの混入が起こり、これを種々の方法
で低減できるにしても、シャロードナーとなるＳｉの濃
度が、１．０Ｘ１０”から１．０ＸＩＯ”ｅｌｍ−’程
度存在する。In the HB method, crystals are usually grown using a quartz ampoule, so Si contamination from the quartz occurs, and even if this can be reduced by various methods, the concentration of Si that becomes a shallow donor is 1.0x10" Approximately 1.0XIO"elm-' exists.
一方、シャローアクセプターとなる炭素もおよそ１．０
Ｘ１０ｉｓから１．０ＸＩＯ”ａｍ−’程度存在する。On the other hand, the carbon that becomes a shallow acceptor is also approximately 1.0
There exists about 1.0XIO"am-' from X10is.
また、ＨＢ法で製造するＧａＡｓ単結晶にはＥＬ２がお
よそ５Ｘ１０”から２ Ｘ １０”■−３程度存在する
。ＨＢ法ではシャロードナーの濃度がシャローアクセプ
ターの濃度より高くなることがあるため、ディープドナ
ーであるＥＬ２だけでは安定して半＃ＰＡｕ性のＧａＡ
ｓを製造することはできない。このため、シャロードナ
ーの濃度を上回るように、ディープアクセプターとなる
Ｃｒをドーピングして半絶縁性のＧａＡｓが製造される
。この場合、ドープされるＣｒの濃度は、１．０Ｘ１０
”から５ Ｘ １０１１０″′である。Further, in the GaAs single crystal produced by the HB method, EL2 exists in the range of about 5 x 10" to 2 x 10" -3. In the HB method, the concentration of shallow donor may be higher than the concentration of shallow acceptor, so EL2, which is a deep donor, can stably produce semi-#PAu GaA.
It is not possible to manufacture s. Therefore, semi-insulating GaAs is manufactured by doping Cr, which serves as a deep acceptor, to a concentration higher than that of the shallow donor. In this case, the concentration of doped Cr is 1.0×10
" to 5 x 10110"'.
ＬＥＣ法では通常、ｐＢＮルツボを用いて単結晶を育成
するため、シャロードナーであるＳＬなどの不純物の濃
度は低く Ｉ Ｘ １０”０１−３以下とすることが可
能である。また、ＬＥＣ法では断熱材等にグラファイト
製の部品を用いるため、通常の方法では炭素の濃度Ｎｓ
＾がやや高＜２Ｘ１０１ｓからＩ Ｘ １０”■−３と
なる。ＬＥＣ法ではこのようにシャローアクセプターと
なる炭素の濃度がシャロードナー（Ｓｉ等）の濃度より
高いため、ディープドナーとなるＥＬ２だけで半Ｍｅ性
のＧａＡｓの製造が可能である。通常のＬＥＣ法ではＥ
Ｌ２の濃度Ｎ ｏ ｏは２ Ｘ １０”ａｍ−″３程度
でありＮ ｏ ｏ ） Ｎ Ｓ Ａなる条件が成立する
ので容易に半絶縁性のＧ ａ Ａ ｓ単結晶が製造でき
る。In the LEC method, a pBN crucible is usually used to grow a single crystal, so the concentration of impurities such as SL, which is a shallow donor, is low and can be lower than I x 10''01-3. Since graphite parts are used as insulation materials, the carbon concentration Ns is
Since ^ is slightly high<2X101s, it becomes I X 10"■-3. In the LEC method, the concentration of carbon, which becomes a shallow acceptor, is higher than the concentration of shallow donors (Si, etc.), so only EL2, which becomes a deep donor, It is possible to produce semi-Me GaAs using the normal LEC method.
Since the concentration N o of L2 is about 2×10"am-"3 and the condition N o ) N S A is satisfied, a semi-insulating Ga As single crystal can be easily produced.
［発明が解決しようとする課題］
しかし、上述したようなＬＥＣ法で育成される半絶縁性
ＧａＡｓ単結晶では、シャローアクセプターとなる炭素
の量が不安定であるため、結晶の抵抗率を安定な一定値
にすることが非常に困難である。一方、結晶中の炭素量
をできるだけ低減させる方策をとると、抵抗率が低下す
るのみでなく、抵抗率のばらつきが更に大きくなってし
まう、その結果、従来のＬＥＣ法で育成される半絶縁性
Ｇａ Ａ ｓ単結晶では、その電気的特性がウェハー面
内、ウェハー間、インゴット間でばらついてしまい、こ
のようなウェハーを用いて電子デバイスを作ると、その
デバイス特性が大きくばらつくという問題が生じていた
。実際、このばらつきが大きいために、電子デバイスを
製造するにあたっては、インゴットの上下のウェハーを
前もって評価してからでないと、そのインゴットが使用
できないという不都合が生じていた。[Problem to be solved by the invention] However, in the semi-insulating GaAs single crystal grown by the LEC method as described above, the amount of carbon that becomes a shallow acceptor is unstable, so it is difficult to stabilize the resistivity of the crystal. It is very difficult to maintain a constant value. On the other hand, if measures are taken to reduce the amount of carbon in the crystal as much as possible, not only will the resistivity decrease, but the variation in resistivity will become even larger.As a result, the semi-insulating properties grown by the conventional LEC method The electrical properties of GaAs single crystals vary within the wafer plane, between wafers, and between ingots, and when electronic devices are made using such wafers, the problem arises that the device properties vary greatly. Ta. In fact, because of this large variation, when manufacturing electronic devices, the ingot cannot be used unless the wafers above and below the ingot are evaluated in advance.
この発明の目的は、ＬＥＣ法による半Ｍ！ＡＭ性ＧａＡ
ｓ単結晶の製造において、結晶インゴットの上下方向全
体に亘って容易に半絶縁性を実現し、もってウェハーの
電気的特性の均一化を図り、これを用いて形成した電子
デバイスの特性のばらつきを防止することにある。The purpose of this invention is to obtain half M! AM GaA
s In the production of single crystals, it is possible to easily achieve semi-insulating properties across the entire vertical direction of the crystal ingot, thereby making the electrical properties of the wafer uniform and reducing the variations in the properties of electronic devices formed using the same. The purpose is to prevent it.
［課題を解決するための手段］
上述したように、ＬＥＣ法においては、単結晶育成時に
混入する炭素の量が不安定であるため、結晶の抵抗率を
安定な一定値にすることが非常に困難であり、単に、結
晶中の炭素量をできるだけ低減させる方策をとると、抵
抗率が低下するのみではなく、抵抗率のばらつきが更に
大きくなる。[Means for solving the problem] As mentioned above, in the LEC method, the amount of carbon mixed in during single crystal growth is unstable, so it is extremely difficult to maintain the resistivity of the crystal at a stable constant value. This is difficult, and if measures are taken to simply reduce the amount of carbon in the crystal as much as possible, not only will the resistivity decrease, but the variation in resistivity will become even larger.
そこで、本発明では、シャローアクセプターとして、炭
素でなく、Ｚｎ等の不純物を用いて結晶の抵抗率を再現
性よく制御する方法を考案した。Therefore, in the present invention, a method has been devised to control the resistivity of the crystal with good reproducibility by using an impurity such as Zn instead of carbon as a shallow acceptor.
すなわち、結晶中に混入する炭素量はできるだけ低減さ
せ、Ｚｎ等の濃度を調節して結晶の抵抗率を制御すると
いうものである。Ｚｎ等の濃度としては、ディープドナ
ーであるＥＬ２の濃度より低く、かつ、Ｓｉなどのシャ
ロードナーの濃度より高くする。ＥＬ２の濃度はおよそ
（５〜２０）Ｘ１０”ｃａ−’であり、Ｓｉなどのシャ
ロードナーの濃度はおよそ（５〜２０） Ｘ １０１４
ｅ１１−’であるからＺｎ等の濃度は（１〜２０）ＸＩ
Ｏ”ＧＷ−”、好ましくは、（２〜５）ＸＩＯ”ａｍ−
’である。That is, the amount of carbon mixed into the crystal is reduced as much as possible, and the resistivity of the crystal is controlled by adjusting the concentration of Zn, etc. The concentration of Zn, etc. is lower than the concentration of EL2, which is a deep donor, and higher than the concentration of shallow donor, such as Si. The concentration of EL2 is approximately (5-20) x 10"ca-', and the concentration of shallow donor such as Si is approximately (5-20) x 1014
Since e11-', the concentration of Zn etc. is (1~20)XI
O"GW-", preferably (2-5)XIO"am-
'is.
原料中にＺｎ等を添加するに当っては、結晶育成開始前
のＧａとＡｓをｐＢＮ製ルツルツボれる際に、Ｚｎ等を
直接添加するか、あるいは前もってＧａ中に所定量のＺ
ｎ等をドープしておく。既に合成した原料を用いる場合
は、その原料をｐＢＮ製ルツルツボれる際に所定量のＺ
ｎ等を同時に入れておくか前もってＺｎ等を添加した合
成原料を使用する。炭素量を低減させるための方法とし
ては、単結晶の引上げに使用するグラファイト部品を使
用前に真空炉内でベーキングしたり、グラファイト部品
を引上げ炉内でベーキングしたり、あるいは、引上げ炉
内のガスをＴｉやＺｒなどのような活性な金属を加熱し
て純化したり、引上げ炉内の圧力を低くしたり、磁場を
印加したりする方法を適用する。もちろん、これら様々
な方法の全部、あるいは一部を併用してよい。When adding Zn, etc. to the raw materials, it is necessary to directly add Zn, etc. when Ga and As are put into a PBN crucible before starting crystal growth, or to add a predetermined amount of Zn to Ga in advance.
Dope n etc. When using a raw material that has already been synthesized, a predetermined amount of Z is added to the raw material when it is put into a pBN crucible.
Synthetic raw materials are used in which Zn, etc. are added at the same time, or Zn, etc. are added in advance. Methods to reduce the amount of carbon include baking the graphite parts used for pulling single crystals in a vacuum furnace before use, baking the graphite parts in the pulling furnace, or using gas in the pulling furnace. Methods such as heating active metals such as Ti and Zr to purify them, lowering the pressure in the pulling furnace, and applying a magnetic field are applied. Of course, all or some of these various methods may be used in combination.
なお、以下の説明では炭素以外の浅いアクセプターとな
る不純物としては、Ｚ ｎ ＨＢ ｅ ｒ Ｍ ｇ ＋
Ｃｄ、Ｍｎ、Ａｇ等があるが、Ｚｎを例にとって説明す
る。In the following explanation, impurities other than carbon that serve as shallow acceptors include Z n HB e r M g +
Although there are Cd, Mn, Ag, etc., Zn will be explained as an example.
［作用］
上述したいくつかの炭素低減法により、ＧａＡｓ中の炭
素量は少なくとも５ Ｘ １０′４ａｍ−’、良好な条
件を選んだ場合にあっては、炭素量を１×ＩＱ１４ａｎ
−’未満とすることができる。このような低炭素化が実
現できるとＧａＡｓ単結晶の抵抗は低下し、時には、炭
素量がシャロードナーであるＳｉの量よりも少なくなる
。[Effect] By using some of the carbon reduction methods mentioned above, the amount of carbon in GaAs can be reduced to at least 5 x 10'4 am-', and if favorable conditions are selected, the amount of carbon can be reduced to 1 x IQ14 am-'.
It can be less than -'. If such a reduction in carbon can be achieved, the resistance of the GaAs single crystal will decrease, and in some cases, the amount of carbon will be less than the amount of Si, which is a shallow donor.
Ｚｎをドープして半絶縁性ＧａＡｓ単結晶を育成すると
、Ｚｎの偏析係数は０．８程度であるため、結晶の頭部
から底部までほぼ同一組成の結晶が得られる。また、Ｚ
ｎの濃度が低いため、育成結晶中の径方向で、温度変動
などによるストリエーションによるＺｎの組成変動がほ
とんどない。When a semi-insulating GaAs single crystal is grown by doping with Zn, a crystal having almost the same composition from the top to the bottom of the crystal can be obtained since the segregation coefficient of Zn is about 0.8. Also, Z
Since the concentration of n is low, there is almost no variation in the composition of Zn due to striations due to temperature fluctuations in the radial direction of the grown crystal.
これによって、比較的均一なＺｎ組成のＧａＡｓ単結晶
を育成することができ、この単結晶インゴットからウェ
ハーを採取して研磨し、このウェハーにＳｉなどのドナ
ー不純物をイオン注入したり、あるいはこの基板の上に
Ｓｉなどのドナー不純物を添加したエピタキシャル層を
成長させて活性層を作りＦＥＴなどの電子デバイスを製
造すると、活性層と半絶縁性の基板の間に均一な空乏層
が形成されるために、ＦＥＴのｇｍ値やしきい値電圧な
どの電子デバイス特性のばらつきを著しく低減させた電
子デバイスの製造が可能となる。As a result, it is possible to grow a GaAs single crystal with a relatively uniform Zn composition, and a wafer is taken from this single crystal ingot and polished, and donor impurities such as Si are ion-implanted into this wafer, or this substrate is When manufacturing electronic devices such as FETs by growing an epitaxial layer doped with donor impurities such as Si on top of the active layer, a uniform depletion layer is formed between the active layer and the semi-insulating substrate. Furthermore, it becomes possible to manufacture electronic devices in which variations in electronic device characteristics such as the gm value and threshold voltage of FETs are significantly reduced.
［実施例］
ＬＥＣ法による結晶育成を開始する前に、Ｚｎを１０″
”ａｍ−’程度高濃度に含有するＧ ａ Ａ ｓ多結晶
を予め作成した。そして、高圧引上げ炉にセラ１−され
たｐＢＮ＠ルツボ内に純度７ＮのＧａおよびＡｓを約４
ｋｇ仕込み、ＧａＡｓ融液中のＺｎ濃度が約４ Ｘ １
０１ｓＣ！＋１−’となるようにＺｎ含有ＧａＡｓ多結
晶を約Ｌｏｇ加えた。これに封止剤であるＢ２０．を６
００ｇ加え、炉内で直接合成を行ない、融液に種結晶を
浸漬してこれを徐々に引き上げて単結晶を育成した。[Example] Before starting crystal growth by LEC method, Zn was
Ga As polycrystals containing a high concentration of "am-" were prepared in advance. Ga and As with a purity of 7N were placed in a pBN crucible placed in a high-pressure pulling furnace.
kg, the Zn concentration in the GaAs melt is approximately 4 x 1
01sC! Approximately Log of Zn-containing GaAs polycrystal was added so as to give +1-'. This is followed by B20, which is a sealant. 6
00g was added and direct synthesis was carried out in the furnace, and a single crystal was grown by immersing a seed crystal in the melt and gradually pulling it up.
得られた単結晶の直径は８０ｎｎ、長さは１７０ｍ、重
量３．７ｋｇであった。結晶の上部から下部にかけて厚
さ４ｍのウェハーを採取し、残りの部分は、厚さ８００
μｍに切断した。これらウェハーはともに鏡面研磨加工
を行なった。厚さ４ｍのウェハーを、赤外吸収法により
、ＥＬ２濃度を測定した結果、ＥＬ２濃度は（１，３〜
１．６）Ｘ１０”ａｍ−’であった。また、インゴット
の上部から下部の各同化率における。ＺｎＪ度を固体質
量分析（Ｓｐａｒｋ ５ｏｕｒｃｅ ＭａｓｓＳｐ
ｅｃｔｒｏｍｅｔｒｙ）法により測定した結果、Ｚｎ濃
度はほぼ（３〜４） Ｘ １０”ａｎ −’であった。The obtained single crystal had a diameter of 80 nn, a length of 170 m, and a weight of 3.7 kg. A wafer with a thickness of 4 m was taken from the top to the bottom of the crystal, and the remaining part was a wafer with a thickness of 800 m.
It was cut into μm. Both of these wafers were subjected to mirror polishing. As a result of measuring the EL2 concentration of a 4 m thick wafer by infrared absorption method, the EL2 concentration was (1,3~
1.6)
As a result of measurement by the electrometry method, the Zn concentration was approximately (3 to 4) x 10'' an -'.
各同化率に対応するＥＬ２濃度およびＺｎ濃度の測定結
果を第１図に示す。同図において、Δ印はＥＬ２濃度の
測定値を、Ｏ印はＺｎ濃度の測定値をそれぞれプロット
したものである。第１図よりＥＬ２ａ度は、インゴット
内でほぼ一定値で分布し、Ｚｎ濃度は上部から下部にか
けてやや増加するもののほぼ均一であることが分かる。FIG. 1 shows the measurement results of EL2 concentration and Zn concentration corresponding to each assimilation rate. In the figure, the Δ mark is a plot of the measured value of EL2 concentration, and the O mark is a plot of the measured value of Zn concentration. From FIG. 1, it can be seen that the EL2a degree is distributed at a substantially constant value within the ingot, and the Zn concentration is almost uniform, although it slightly increases from the top to the bottom.
Ｚｎの実効偏析係数はほぼ０．８であった。また。The effective segregation coefficient of Zn was approximately 0.8. Also.
ウェハーから７膿角の試料を切り出し、ファンデルパラ
（Ｖａｎ ｄｅｒ Ｐａｕｗ）法により抵抗率およ
び移動度を測定した結果、抵抗率はインゴット全域で（
３〜５）×１０’ΩＧ、移動度は６０００〜７０００ａ
Ｊ／ＶＳテあり、結１％＋７１成長方向の均一性は良好
であった。この結晶のカーボン濃度は、ＬＶＭ （Ｌｏ
ｃａｌｉｚｅｄ Ｖｉｂｒａｔｉｏｎ Ｍｏｄｅ）
を利用したＦＴＩＲ法（フーリエ変換赤外分光法）によ
る測定では検出下限（５Ｘ １０１４ｃａ −”） 〜
８ Ｘ １０”ａｍ −３の範囲であった。A sample of 7 pus angle was cut from the wafer and the resistivity and mobility were measured by the Van der Pauw method. As a result, the resistivity was (
3~5)×10'ΩG, mobility is 6000~7000a
With J/VS test, the uniformity in the growth direction of 1%+71 was good. The carbon concentration of this crystal is LVM (Lo
Calized Vibration Mode)
In measurement by FTIR method (Fourier transform infrared spectroscopy) using
It was in the range of 8×10”am −3.
上記と同一の方法でＺｎドープ半絶縁性ＧａＡＳ単結晶
を４本育成し、ロット間の抵抗率の変動範囲を調べ、従
来方法により育成したアンドープ半絶縁性結晶の場合と
比較した結果を第２図に示す。We grew four Zn-doped semi-insulating GaAS single crystals using the same method as above, examined the variation range of resistivity between lots, and compared the results with those of undoped semi-insulating crystals grown using the conventional method. As shown in the figure.
同図において、符号ａ、ｂ、Ｑ、ｄで示すのが本発明を
適用して得られた４本のロットについての測定結果、符
号Ａ、Ｂ、Ｃ，Ｄで示すのが従来法を適用して得られた
４本のロットについての測定結果をそれぞれ表わす。In the figure, the symbols a, b, Q, and d are the measurement results for four lots obtained by applying the present invention, and the symbols A, B, C, and D are the measurement results obtained by applying the conventional method. The measurement results for the four lots obtained are shown respectively.
第２図から明らかなように、従来方法によるアンドープ
半絶縁性結晶は、ロフト間、ウェハー間で抵抗率が９
Ｘ １０’〜９ Ｘ １０’Ω１と変動するのに対し１
本発明方法によるＺｎドープ半絶縁性結晶は１、抵抗率
のばらつきが（２〜５）ＸＩＯ’Ω備と少なく、再現性
良く一定範囲内に抑えられていることが分かる。As is clear from Figure 2, the undoped semi-insulating crystal produced by the conventional method has a resistivity of 9 between lofts and between wafers.
X 10' to 9 X 10' Ω1
It can be seen that the Zn-doped semi-insulating crystal produced by the method of the present invention has a small variation in resistivity of (2 to 5) XIO'Ω, which is suppressed within a certain range with good reproducibility.
本実施例によって得られたＺｎドープＧａＡｓ単結晶を
鏡面加工した後、イオン注入法によりシリコンを注入し
て活性層を形成し、ＭＥＳＦＥＴを作成した。イオン注
入条件は、加速電圧１００ＫｅＶ、注入量２ＸＯ１２０
−２とし、活性化はプラスｖｃＶＤｓ ｉ３Ｎ４膜を保
護膜として８３０°Ｃ１１０分間のアニールで行なった
。ソース、ドレイン電極には、Ａｕ−Ｇｅ−Ｎｉ、ゲー
ト電極にはＴｉ−Ｐｔ−Ａｕを用いた。ゲート長は２μ
ｍ、ゲート幅は５μｍ、ソース、ドレイン間は６μｍと
した。上記ＭＥＳＦＥＴについてデバイス特性の評価を
行なった結果、しきい値電圧ｖｔｈおよびそのインゴッ
ト内の変動幅は表１に示す通りであった。同表より本発
明方法によるＺｎドープＧａＡｓ単結晶は、従来のアン
ドープ結晶に比べてしきい電圧の変動幅が著しく改善さ
れることが分かる。After mirror-finishing the Zn-doped GaAs single crystal obtained in this example, silicon was implanted by ion implantation to form an active layer and a MESFET was fabricated. The ion implantation conditions were an acceleration voltage of 100KeV and an implantation amount of 2XO120.
−2, and activation was performed by annealing at 830° C. for 110 minutes using a positive vcVDs i3N4 film as a protective film. Au-Ge-Ni was used for the source and drain electrodes, and Ti-Pt-Au was used for the gate electrode. Gate length is 2μ
m, the gate width was 5 μm, and the distance between the source and drain was 6 μm. As a result of evaluating the device characteristics of the above MESFET, the threshold voltage vth and its variation range within the ingot were as shown in Table 1. From the same table, it can be seen that the Zn-doped GaAs single crystal produced by the method of the present invention has a significantly improved threshold voltage fluctuation range compared to the conventional undoped crystal.
表Ｉ ＦＥＴ特性の比較例
なお、半絶縁化に寄与するシャローアクセプタとしては
、Ｚｎに限定されるものでなく、ＢｅやＭｇ＊ Ｃｄｔ
Ｍｎ、Ａｇ等も使用することが可能である。ただし、
Ｚｎ以外の上記シャローアクセプタは、Ｚｎに比べ偏析
係数が１からより離れているので、結晶軸方向に沿った
組成変動が大きくなる。Table I Comparative example of FET characteristics Note that the shallow acceptor that contributes to semi-insulating is not limited to Zn, but also Be, Mg*Cdt
Mn, Ag, etc. can also be used. however,
The above-mentioned shallow acceptors other than Zn have a segregation coefficient further away from 1 than Zn, so that compositional fluctuations along the crystal axis direction are large.
［発明の効果］
以上説明したようにこの発明は、ＧａＡｓ化合物半導体
の単結晶を育成する際に、ＧａＡｓ結晶中の固有欠陥た
るＥＬ２濃度よりも低く、かつ浅いドナーとなる不純物
の濃度よりも高くなるように炭素以外の浅いアクセプタ
ー不純物を添加して結晶の育成を行なうようにしたので
、結晶インゴットの軸方向に沿ってほぼ均一な抵抗率を
有する半絶縁性ＧａＡｓ単結晶を再現性良く育成でき、
これによってこの結晶を用いて形成した電子デバイスの
電気的特性のばらつきを防止し１歩留りを向上させるこ
とができるようになる。[Effects of the Invention] As explained above, the present invention has the advantage that when growing a single crystal of a GaAs compound semiconductor, the concentration of EL2, which is an inherent defect in the GaAs crystal, is lower than the concentration, and the concentration of impurities that are shallow donors is higher than the concentration of EL2, which is an inherent defect in the GaAs crystal. By growing the crystal by adding a shallow acceptor impurity other than carbon, we were able to grow a semi-insulating GaAs single crystal with almost uniform resistivity along the axial direction of the crystal ingot with good reproducibility. ,
This makes it possible to prevent variations in the electrical characteristics of electronic devices formed using this crystal and improve the yield.
第１図は、本発明を適用して得られたＺｎドープＧａＡ
ｓ単結晶の各同化率におけるＥＬ２濃度およびＺｎ１度
を示す図。
第２図は、従来方法により得られたアンドープ半絶縁性
単結晶と、本発明方法により行なわれたＺｎドープ半絶
縁性単結晶のロフト間の抵抗率の変動幅を示す図である
。
第２図
本荘ＩＩＩ目（絶倒： 鉋束伊コ
（２ｎ￥−７，ｌｉ７由＼坑き漬）：（アンＬ′−ｒ高
憩坑きも融（Ωｃｒｎ）
手続肴行正書（自発）FIG. 1 shows Zn-doped GaA obtained by applying the present invention.
s A diagram showing the EL2 concentration and Zn1 degree at each assimilation rate of the single crystal. FIG. 2 is a diagram showing the range of variation in resistivity between the lofts of an undoped semi-insulating single crystal obtained by the conventional method and a Zn-doped semi-insulating single crystal obtained by the method of the present invention. Figure 2 Honjo III (absolutely defeated: Iko Tsuzuka (2n ¥-7, li7yu\Kingzuke): (An L'-r Takaikiki Kimo Fu (Ωcrn) Procedural supplementary book (spontaneous)
Claims (2)
つ浅いドナーとなる不純物の濃度よりも高くなるように
炭素以外の浅いアクセプターとなる不純物を含有してな
ることを特徴とする半絶縁性ＧａＡｓ化合物半導体単結
晶。(1) Semi-insulating, characterized by containing an impurity other than carbon that becomes a shallow acceptor so that the concentration is lower than the EL2 concentration, which is an inherent defect in the crystal, and higher than the concentration of an impurity, which is a shallow donor. GaAs compound semiconductor single crystal.
ＧａＡｓ結晶中の固有欠陥たるＥＬ２濃度よりも低く、
かつ浅いドナーとなる不純物の濃度よりも高くなるよう
に炭素以外の浅いアクセプターとなる不純物を添加して
結晶の育成を行なうようにしたことを特徴とする半絶縁
性ＧａＡｓ化合物半導体単結晶の製造方法。(2) When growing a single crystal of GaAs compound semiconductor,
Lower than the EL2 concentration, which is an inherent defect in the GaAs crystal,
A method for producing a semi-insulating GaAs compound semiconductor single crystal, characterized in that the crystal is grown by adding an impurity other than carbon to serve as a shallow acceptor so that the concentration of the impurity is higher than that of an impurity that serves as a shallow donor. .
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4250688A JPH01215799A (en) | 1988-02-24 | 1988-02-24 | Semi-insulating gaas compound semiconductor single crystal and production thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4250688A JPH01215799A (en) | 1988-02-24 | 1988-02-24 | Semi-insulating gaas compound semiconductor single crystal and production thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH01215799A true JPH01215799A (en) | 1989-08-29 |
| JPH0476355B2 JPH0476355B2 (en) | 1992-12-03 |
Family
ID=12637950
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP4250688A Granted JPH01215799A (en) | 1988-02-24 | 1988-02-24 | Semi-insulating gaas compound semiconductor single crystal and production thereof |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH01215799A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0274597A (en) * | 1988-09-08 | 1990-03-14 | Hitachi Cable Ltd | Chromium-doped semi-insulative gallium-arsenic single crystal and production thereof |
| US5041186A (en) * | 1987-11-30 | 1991-08-20 | Kabushiki Kaisha Toshiba | Method for manufacturing compound semiconductor single crystals using a hydrogen monitor gas |
| JP2005350295A (en) * | 2004-06-09 | 2005-12-22 | Sumitomo Electric Ind Ltd | Semiconductor crystal and production method therefor |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS63201097A (en) * | 1987-02-13 | 1988-08-19 | Sumitomo Electric Ind Ltd | Semiinsulating gallium-arsenic single crystal |
-
1988
- 1988-02-24 JP JP4250688A patent/JPH01215799A/en active Granted
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS63201097A (en) * | 1987-02-13 | 1988-08-19 | Sumitomo Electric Ind Ltd | Semiinsulating gallium-arsenic single crystal |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5041186A (en) * | 1987-11-30 | 1991-08-20 | Kabushiki Kaisha Toshiba | Method for manufacturing compound semiconductor single crystals using a hydrogen monitor gas |
| JPH0274597A (en) * | 1988-09-08 | 1990-03-14 | Hitachi Cable Ltd | Chromium-doped semi-insulative gallium-arsenic single crystal and production thereof |
| JP2005350295A (en) * | 2004-06-09 | 2005-12-22 | Sumitomo Electric Ind Ltd | Semiconductor crystal and production method therefor |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0476355B2 (en) | 1992-12-03 |
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