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Growth of Binary Compound Semiconductors of Uniform Compositions By One-Directionnal Growth Method with a Nonuniform Concentration Distribution

非均匀浓度分布的单向生长法生长均匀成分的二元化合物半导体

基本信息

批准号：
11555061
负责人：
MAEKAWA Toru
金额：
$ 7.87万
依托单位：
Toyo University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2001
项目状态：
已结题

项目摘要

I investigated the validity of a new growth method for producing binary semiconductor crystals, which have uniform compositions, utilizing microgravity conditions. First, I developed a calculation method of growth of binary semiconductor crystals from a macroscopic point of view based on thermofluid dynamics. The shape and movement of the solution-crystal interfaces as well as the flow, temperature and concentration fields can be estimated efficiently. The growth process of an InAs-GaAs binary crystal by the Bridgman and zone methods were investigated and the following results were obtained :(a) Bridgman method :(1) The temperature field is not seriously deformed by convection since the Prandtl number of the molten compound semiconductors is very small.(2) The concentration field and the solution-crystal interface are deformed by buoyancy convection even under microgravity when the crystal growth direction is perpendicular to the residual gravity, since the Schmidt number is large.(3) As the crystal size and the heat flux increase, the deformation of the concentration field and the solution-crystal interface becomes more extensive.(b) Zonemethod :(1) The convective velocity is reduced by employing the zone method.(2) The velocity and the deformation of the temperature and concentration fields and the solution-crystal interfaces are reduced remarkably and, as a result, supercooling is suppressed by reducing the zone width.(3) A uniform In0.3Ga0.7As single crystal may be grown by reducing the zone width to 15 mm and setting the temperature gradient in the zone at 10 K/cm.

我研究了一种新的生产二元半导体晶体的生长方法的有效性，该方法具有均匀的成分，利用微重力条件。首先，基于热流体动力学理论，从宏观角度发展了二元半导体晶体生长的计算方法。可以有效地估计溶液-晶体界面的形状和运动以及流场、温度场和浓度场。本文研究了用Bridgman法和区域法生长InAs-GaAs二元晶体的过程，得到以下结果：（a）Bridgman法：（1）由于化合物半导体熔体的普朗特数很小，对流对温度场的影响不大。(2)由于施密特数较大，当晶体生长方向垂直于剩余重力时，即使在微重力下，浓度场和溶液-晶体界面也会因浮力对流而变形。(3)随着晶体尺寸和热流密度的增大，浓度场和固溶体-晶体界面的变形范围增大。(b)分区法：（1）采用分区法降低对流速度。(2)温度场、浓度场和固溶体-晶体界面的速度和变形显著减小，因此，通过减小区域宽度来抑制过冷。(3)通过将区域宽度减小到15 mm并且将区域中的温度梯度设定为10 K/cm，可以生长均匀的In0.3Ga0.7As单晶。