Novel Ga2O3(Gd2O3) passivation techniques to produce low D-it oxide-GaAs interfaces

Molecular beam epitaxy (MBE) has been extended to fabricate heterostructures of Ga2O3(Gd2O3)-GaAs. Two processes were used: (1) in situ approach in which the oxide molecules were deposited on freshly prepared GaAs (1 0 0), and (2) ex situ approach which comprises thermal desorption of native oxides of GaAs and subsequent Ga2O3(Gd2O3) film deposition on GaAs (1 0 0) wafers all tinder ultra-high vacuum, A low interface recombination velocity S of 9000 cm/s equivalent to an interface state density D-it in the upper 10(10) cm(-1) eV(-1) range has been inferred for the ex situ processed samples. In comparison, an interface recombination velocity of 4000-5000 cm/s and an interface state density D-it in the lower 10(10) cm(-2) eV(-1) range were obtained for the in situ processed samples. The ex situ technique provides excellent passivation for GaAs wafers which may have been exposed to room air and/or processing environments during fabrication of devices such as FETs, HBTs, etc.