X-RAY PHOTOELECTRON-SPECTROSCOPY STUDY OF GAAS SURFACE-EXPOSED TO A RF HYDROGEN PLASMA

Using x-ray photoelectron spectroscopy analysis, it is shown that hydr ogen plasma treatment of the gallium arsenide surface induces a modifi cation of the superficial stoichiometry. The resulting surface composi tion presents a gallium enrichment and is the same whatever the initia l composition. The departure from the stoichiometry increases with the plasma power. After the plasma treatment, the absence of arsenic oxid ation and an abnormal gallium suboxidation state is observed. Moreover , these new gallium and arsenic oxidation states are stable when the s ample is left in the air.