In situ silane passivation of gallium arsenide and deposition of high-permittivity gate dielectric for MOS applications

Abstract

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 Si H4 annealing were performed prior to Hf O2 deposition. X-ray photoelectron spectroscopy and transmission electron microscopy results show that the Si H4 surface passivation can effectively suppress the formation of Ga or As oxide during the Hf O2 deposition process. TaNHf O2 GaAs metal-oxide-semiconductor (MOS) capacitors were fabricated. Electrical characteristics show that an equivalent oxide thickness of 2.03 nm and a low leakage current density of 1.55× 10-4 A cm2 at VFB -1 V gate bias as well as excellent thermal stability were achieved with the Si H4 surface passivation. © 2007 The Electrochemical Society.