REFLECTANCE-DIFFERENCE STUDY OF SURFACE-CHEMISTRY IN MOVPE GROWTH

With the advent of the reflectance-difference (RD) technique the electronic configurations of III-V surfaces can be probed also under the non-ultra-high vacuum (UHV) conditions prevailing during metalorganic vapour phase epitaxy (MOVPE). In this paper the surface chemistry involved in the MOVPE growth of GaAs from triethylgallium and arsine is studied in a growth system where the pressure can be changed from high-vacuum (10(-3) Torr) to low-pressure (1 Torr) conditions. Studies of the GaAs surface during its exposure to triethylgallium and to arsine are presented. Growth oscillations detected in real time are used to characterize growth and to investigate three-dimensional island formation during Ga saturation. Finally, growth oscillations are used to study the kinetics of the regeneration of ideal, As-terminated, surface conditions.