半绝缘砷化镓单晶中碳微区分布的研究

Micro-distribution of carbon in semi-insulating gallium arsenide

通过AB腐蚀 (由Abrahams和Buiocchi发明的腐蚀方法 ,简称AB腐蚀 )、KOH腐蚀 ,经金相显微镜观察、透射电子显微镜能谱分析、电子探针x射线微区分析 ,对液封直拉法生长的非掺半绝缘砷化镓单晶中碳的微区分布进行了分析研究 .实验结果表明 ,碳的微区分布受单晶中高密度位错网络结构的影响 .高密度位错区 ,位错形成较小的胞状结构 ,且胞内不存在孤立位错 ,碳在单个胞内呈U型分布 ;较低密度位错区 ,胞状结构直径较大 ,且胞内存在孤立位错 ,碳在单个胞内呈W型分布 .

Micro-distribution of C acceptor defect in semi-insulating gallium arsenide (SI-GaAs) wafer has been investigated by means of chemical etching, microscopic observation, transmission electron microscope, eelectron probe x-ray microanalyzer. Experimental results show that there is a corresponding relationship between the distribution of C impurity and dislocation density in a wafer. In relatively high dislocation density areas, dislocations form relatively small cells with few isolated dislocation within each cell. Here the profile of C distribution in the area of a cell is 'U'-shaped. The cell diameter increases as the dislocation density decreases, and the dislocations form relatively large cells with a few isolated dislocations within each cell. The profiles of C distribution in the area of a cell is 'W'-shaped.