Controlled intrinsic carbon doping in MOVPE-grown GaAs layers by using TMGa and TBAs

Homoepitaxial GaAs layers were grown by low-pressure metalorganic vapor phase epitaxy (MOVPE), by using the metalorganic precursors trimethylgallium (TMGa) and the low-toxicity, low-dissociation-temperature tertiary-butyl arsine (TBAs), in order to exploit the phenomenon of controlled intrinsic carbon doping. Low-temperature photoluminescence, Hall effect and capacitance-voltage measurements were performed on the grown samples. The intrinsic carbon doping was studied as a function of: (i) the growth temperature (ranging between 5001C and 6401C), (ii) the V/III precursor ratio in the vapour phase (ranging between 1 and 25) and (iii) the influence of GaAs substrate mis orientation (01 and 21off toward 110). Although a reduced carbon incorporation rate was expected by using TBAs, which is a benefit in obtaininghigh purity GaAs, intrinsically p-doped GaAs layers with a hole concentrations up to 6.5 1018 cm 3 and a correspondingRT mobility in the range (100–400) cm2 /V s were obtained.