CORRELATION BETWEEN ARSENIC PRECIPITATES AND VACANCY-TYPE DEFECTS IN LOW-TEMPERATURE-GROWN GAAS

We have utilized x-ray photoelectron and variable energy positron beam spectroscopies for depth profiling excess arsenic, arsenic precipitates, and vacancy-type defects in GaAs grown by molecular beam epitaxy at low temperatures (LT-GaAs). XPS results show about 1.3% excess arsenic in as-grown LT-GaAs and a non-uniform depth profile of arsenic concentration in annealed LT-GaAs. Doppler broadening of the positron-electron annihilation radiation (S parameter) reveals a non-uniform depth profile of defects in annealed LT-GaAs. We observe a clear correlation between the depth profile of the S parameter and As in annealed LT-GaAs.