Surface morphology of S or Se terminated GaAs(111)B

The surface roughness and stability of S or Se-terminated GaAs(111)B has been investigated by reflection high energy electron diffraction (RHEED), 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 550°C heating. AES measurements showed that the roughness of the S-terminated surface increased by 400°C heating, while the Se-terminated surface was stable up to 500°C heating. AFM images of both surfaces showed that the roughness of the S-terminated surface was larger than that of the Se-terminated surface. These measurements have revealed the difference in thermal stability between the S- and Se-terminated surfaces.