SURFACE-MORPHOLOGY OF S OR SE TERMINATED GAAS(111)B

The surface roughness and stability of S or Se-terminated GaAs(111)B h as been investigated by reflection high energy electron diffraction (R HEED), Auger electron spectroscopy (AES) and atomic force microscopy ( AFM). RHEED streak patterns of S-terminated GaAs(111)B surfaces turned into spot patterns with increasing heating temperature. Se-terminated surfaces, on the other hand, kept the streak pattern until 500 degree s C heating. AES measurements showed that the roughness of the S-termi nated surface increased by 400 degrees C heating, while the Se-termina ted surface was stable up to 500 degrees C heating. AFM images of both surfaces showed that the roughness of the S-terminated surface was la rger than that of the Se-terminated surface. These measurements have r evealed the difference in thermal stability between the S- and Se-term inated surfaces.