SURFACE-STRUCTURE OF (100) GAP GROWN BY GAS SOURCE MOLECULAR-BEAM EPITAXY

In situ reflection high-energy electron diffraction analysis was used to investigate the surface structure of the GaP epitaxial layers grown on (100) GaP substrates by gas source molecular beam epitaxy as a function of substrate temperature and V/III flux ratio. It was found that for GaP, column V and column III stabilized surfaces corresponded to the (2×4) and (4×2) reconstruction pattern, respectively, which is characteristic of most all III-V binary compound semiconductors. In the transition region, however, the surface exhibited a ((19)1/2 ×4 reconstruction pattern. At substrate temperatures below 660 °C and 685 °C for P- and Ga-stabilized surfaces, respectively, the surface structure was insensitive to temperature. Beyond 660 and 690 °C, the surface structure exhibited an exponential flux dependence with increasing substrate temperature.