NOVEL GA2O3(GD2O3) PASSIVATION TECHNIQUES TO PRODUCE LOW D-IT OXIDE-GAAS INTERFACES

Molecular beam epitaxy (MBE) has been extended to fabricate heterostru ctures of Ga2O3(Gd2O3)-GaAs. Two processes were used: (1) in situ appr oach in which the oxide molecules were deposited on freshly prepared G aAs (1 0 0), and (2) ex situ approach which comprises thermal desorpti on of native oxides of GaAs and subsequent Ga2O3(Gd2O3) film depositio n 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 stat e density D-it in the upper 10(10) cm(-1) eV(-1) range has been inferr ed for the ex situ processed samples. In comparison, an interface reco mbination 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 si tu processed samples. The ex situ technique provides excellent passiva tion for GaAs wafers which may have been exposed to room air and/or pr ocessing environments during fabrication of devices such as FETs, HBTs , etc.