COMPARISON OF SI AND GAAS INTERFACES RESULTING FROM THERMAL AND PLASMA OXIDATION/

X-ray photoelectron spectroscopy (XPS) analyses of oxides produced by thermal and plasma oxidation of GaAs show that electron cyclotron reso nance (ECR) plasma oxidation favors what is thought to be the more des irable (from the point of view of electronic passivation) As+5 oxidati on state while thermal oxidation favors the lower oxidation state, As3 Thermal oxidation produces a Ga-rich oxide, whereas the ECR plasma o xides are nearly stoichiometric. Also, thermal oxidation removes As-(0 ) during the initial stage. XPS shows that thermal and ECR plasma Si o xides have different structures. In situ and real time ellipsometry st udies indicate that thermal and ECR plasma oxidations yield different film growth kinetics for both GaAs and Si. In particular there are no strong substrate orientation effects for the ECR plasma oxidation of G aAs and Si in the initial stage of oxidation. The similarities in our Si and GaAs oxidation results enable models to emerge based on the dom inance of the highly reactive plasma generated oxidant species for pla sma oxidation and molecular oxygen for the thermal case. (C) 1997 Amer ican Vacuum Society.