In Situ Silane Passivation of Gallium Arsenide and Deposition of High-Permittivity Gate Dielectric for MOS Applications

We demonstrate an in situ surface passivation technique for the formation of high-permittivity gate dielectric on GaAs using a multiple-chamber metallorganic chemical vapor deposition system. Vacuum annealing and annealing were performed prior to deposition. X-ray photoelectron spectroscopy and transmission electron microscopy results show that the surface passivation can effectively suppress the formation of Ga or As oxide during the deposition process. metal-oxide-semiconductor (MOS) capacitors were fabricated. Electrical characteristics show that an equivalent oxide thickness of and a low leakage current density of at gate bias as well as excellent thermal stability were achieved with the surface passivation.