GROWTH OF HIGH QUALITY SEMICONDUCTORS BY CONTAINER LESS METHOD UNDER MICROGRAVITY

本研究是作为日本、美国、日本和美国之间的国际联合研究进行的。中国和德国。首先采用垂直布里奇曼法在衬底上生长了未掺杂的GaSb、掺Te的GaSb和（Ga，Al）Sb。结果表明，对未掺杂的GaSb熔体进行预生长退火，可以大大降低位错密度。然后，将通过直拉法生长的Te掺杂的GaSb从一端在垂直布里奇曼炉中熔化，并使用未熔化部分作为籽晶进行再生长。结果表明，在地面上存在强烈的对流，对流引入杂质条纹，使熔体完全混合。(Ga用垂直布里奇曼法成功地生长了（Al，Al）Sb。(Ga用X射线形貌仪和X射线三晶衍射仪（TCD）研究了我国返回式卫星空间生长的Te掺杂GaSb晶体。结果发现，位错密度大大降低，生长进行无接触。在无接触生长的部分中，观察到沉淀物的存在。结果表明，沉淀物可能是由相对高掺杂的Te组成。TCD也表明在无接触条件下生长的晶体质量很高。在美国进行了模型材料的脱体凝固试验，并对微重力条件下的脱体生长进行了评述。

The present studies were carried out as an international joint research among Japan, U.S.A., China and Germany. At first, undoped GaSb, Te doped GaSb and (Ga, Al) Sb were grown on ground by vertical Bridgman method. It was found that a great reduction of dislocation density in undoped GaSb was achieved by pre-growth annealing of GaSb melt. Then, Te doped GaSb which has been grown by Czochralski method was melted in the vertical Bridgman furnace from one end and regrowth was conducted employing un-melted part as a seed. It turned out on ground there was strong convection which introduces impurity Striations and makes the melt completely mix. (Ga, Al) Sb was successfully grown by vertical Bridgman method. (Ga, Al) Sb is suitable to study the elementary process of impurity doping taking Al as an impurity the thermodynamical properties of which has been well known.Te doped GaSb grown in space by Chinese recoverable satellite has been investigated by X-ray topograph and X-ray 3-crystal diffractometry (TCD). It was found that dislocation density is greatly reduced where the growth was conducted contact free. In the part of the contact free growth, the presence of precipitates was observed. It was suggested that the precipitates were probably composed of Te which was relatively highly doped. TCD also showed the quality of the crystal grown under contact free condition was very high. In US side, Detached solidification with model materials were conducted and the detached growth under microgravity was reviewed.