Characterization of Lattice Sites and Compensation Mechanism in Heavily Si-Doped GaAs with Laser Raman Spectroscopy

Lattice sites in heavily Si-doped GaAs have been investigated by means of Raman spectroscopy. Localized vibrational modes (LVM) due to Si Ga -V Ga complex and Si Ga were observed as well as Si Ga -Si As pair and Si As modes. Raman scattering efficiency was obtained from the spectrum area of each mode. The concentrations of these four Si-related sites were estimated, and the results indicate that the carrier compensation mechanism after annealing is dominated by Si Ga -V Ga acceptors and/or Si Ga -Si As neutral pairs depending on the annealing conditions. The compensation mechanism of the as-grown sample and Si-implanted GaAs has also been studied.