Thermal annealing of semi-insulating GaAs under controlled arsenic pressure

Abstract
Bulk, undoped, semi-insulating, liquid encapsulated Czochralski GaAs crystals have been annealed under controlled arsenic pressures, and the uniformities of EL2 concentration and resistivity were investigated. Crystals were grown from different melt compositions from Ga rich to As rich. Arsenic pressure was changed from 0 (vacuum) to 3.4×103 Torr. As a result, it was found that both EL2 concentration and resistivity in the crystal grown from As-rich melt have the lowest fluctuations around 530 Torr arsenic pressure.