Heavily Si-doped GaAs grown by low-pressure metalorganic chemical vapor deposition using tertiarybutylarsine and silane

Heavy Si doping was studied for low-pressure metalorganic chemical vapor deposition of GaAs by using tertiarybutylarsine (tBAs) as a group-V source and silane (SiH₄) as a doping source gas. The Si doping efficiency was higher by one order of magnitude when tBAs was used instead of arsine (AsH ₃). The maximum electron concentration was 9.0×10¹⁸ cm^-3, which is slightly higher than that obtained for AsH₃ (5.9×10¹⁸ cm^-3). The slight increase of the maximum concentration is considered to be due to a reduction of the carrier compensating center generated in high SiH₄ partial pressure conditions. Generation of the electrical compensating center is assigned to be related with the carbon incorporation from alkylsilanes during growth.