EFFECTIVE SI-PLANAR DOPING OF GAAS BY MOVPE USING TERTIARYBUTYLARSINE

We demonstrate highly effective Si planar doping of GaAs by atmospheric-pressure metalorganic vapor phase epitaxy (MOVPE) using tertiarybutylarsine (tBAs) as an alternative arsenic source. The Si incorporation coefficient using tBAs is always higher than that using arsine. The dependence of the Si incorporation coefficient on the group-V precursor flow rate and the gas flow velocity differs greatly between group-V precursors. This indicates that the gas phase reactions between group-V and dopant source dominate the Si doping process, regardless of group-III precursor. We applied a kinetic simulation to the pyrolysis of group-V precursors and confirmed that a large amount of AsH2 exists in the gas phase when using tBAs. We propose that the reactions between As species radicals and silane occur, producing silylarsine (H2AsSiH3) and that silylarsine is abundant for tBAs. Silylarsine rather than SiH2 should be the most significant product contributing to the Si doping reactions.