X‐ray analysis of GaAs surface reconstructions in H2 and N2 atmospheres

In this work, we demonstrate the first in situ study of GaAs using grazing incidence x‐ray scattering during processing at 100 Torr prior to epitaxial film growth. Our results indicate that the native oxide is removed and a well‐ordered surface reconstruction is established at temperatures as low as 500 °C in hydrogen. In contrast, no surface reconstruction is observed when the substrate is heated in nitrogen at temperatures as high as 585 °C while comparable heating in hydrogen causes surface degradation in the form of liquid Ga droplets. These results suggest that a chemically induced surface transformation occurs rather than oxide evaporation during thermal treatment.