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Precise measurement of diffusion coefficient in semiconductor melt under strong magnetic field

强磁场下半导体熔体扩散系数的精确测量

基本信息

批准号：
13650806
负责人：
INATOMI Yuko
金额：
$ 1.09万
依托单位：
The Institute of Space and Astronautical Science
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2002
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-13650806/
关键词：
Diffusion coefficient Strong magnetic field Convection Semiconductor melt Space experiment Hard sphere model In-Sn Ga-doped Ge

项目摘要

In the present study, diffusion coefficients in semiconductor melt were measured precisely by utilization of a strong static magnetic field from the melting point of the specimen to 1500 K and then the measured data were compared with those obtained in the microgravity environment and with the estimated values by a hard sphere model.Some experimental conditions for diffusion experiment in a static magnetic field were derived by a numerical simulation based of a fine element method. Based on the numerical result, the diffusion experiments for In-Sn, Ga-doped Ge, Ge-Si and In_*Ga_<1*>As melts were performed using an image furnace in a static magnetic field. The obtained results for the inter-diffusion coefficients were as follows.1. InSn : The obtained coefficients near the melting point agreed well with those estimated by a hard sphere model However, the temperature dependency of the experimental values at high temperature was almost same as the space experiment result. The physical model for diffusion process in a so-called "simple liquid" should be modified based on the experimental data obtained in higher temperature.2. Ga-doped Ge and Ge-Si : The obtained coefficients were much higher than those estimated by the hard sphere model. The results supports validity of the Itami's model which assumes molten Ge has a structure with a weak covalent bonding between the molecules.3. In_*Ga_<1*>As : No reliable data was obtained by the present method due to the segregation of the solute species, because die segregation coefficient was large in the pseude-binary phase diagram. A shear cell method with an application of strong static magnetic field is a promising way to improve reliability of the experimental data in the case of alloy with a large segregation coefficient.

在本研究中，利用强稳恒磁场精确测量了半导体熔体从熔点到1500 K的扩散系数，并与微重力环境下的测量值和硬球模型的估算值进行了比较，通过数值计算，导出了稳恒磁场中扩散实验的一些实验条件，并对实验结果进行了分析。基于精细单元法的模拟。在此基础上，利用图像炉在静磁场中进行了In-Sn，Ga掺杂Ge，Ge-Si和In_*Ga_（1*）As熔体的扩散实验。得到的互扩散系数结果如下. InSn：在熔点附近的系数与硬球模型的估算值吻合较好，但在高温下的温度依赖性与空间实验结果基本一致。根据高温下的实验数据，对“简单液体”中扩散过程的物理模型进行修正. Ga掺杂的Ge和Ge-Si：得到的系数远高于硬球模型估计的系数。研究结果支持了伊塔米的模型，该模型假设熔融Ge具有分子间弱共价键的结构. In_*Ga_（1*）As：由于准二元相图中溶质的分凝系数较大，导致溶质分凝，用本方法不能得到可靠的数据。在偏聚系数较大的合金中，应用强静磁场的剪切元法是一种很有前途的方法，可以提高实验数据的可靠性。