A Study of Annealing Behavior of EL2 and EL6 Groups in SI-GaAs

AbstractWe present annealing behavior for EL2 and EL6 groups as dominant deep levels in semiinsulating GaAs using Photo Induced Transient Spectroscopy (PITS) measurement. During rapid thermal annealing, a relation has been identified between EL2 group at 0.79 and 0.82 eV and EL6 group at 0.24, 0.27 and 0.82 eV below the conduction band. It is found that they may be close in structure, and belong to the EL2 and EL6 groups, respectively. In rapidly annealed samples, the quantity of all defects in the EL2 group increases, while that in the EL6 group decreases. However, by furnace annealing at 950°C for 5 hours, some of the defects in the EL2 group break up, and the quantity of all defects in the EL6 group increases. It is suggested that the EL2 group and EL6 group are related in their microscopy structures. We then discuss a relation between the two groups and their origins.