Effects of point defect distribution on arsenic precipitation in low-temperature grown III-V arsenides

The behavior of As precipitation in low-temperature grown III-V arsenides is investigated and correlated with the doping level, crystal bond strength, and dislocation density. Experimental results reveal that the doping level affects the concentration of charged defects, such as vacancy and antisite point defects, and hence leads to the selective precipitation of excess As in homojunctions. For heterostructures, As precipitates tend to condense in materials with a lower bond strength due to differences in point defect concentrations between the materials. In addition, dislocations are found to be a vacancy source that facilitates As precipitation around them. These results indicate that column III vacancies play an important role in As precipitation of low-temperature grown III-V arsenides. (C) 1999 American Institute of Physics. [S0021-8979(99)07917-7].