HOLE INJECTION AND ETCHING STUDIES OF GAAS USING THE SCANNING ELECTROCHEMICAL MICROSCOPE

A scanning electrochemical microscope (SECM) was used as an analytical tool to study the etching of GaAs surfaces. Hole injection from several electrogenerated oxidants to n-type, p-type, and undoped GaAs was examined by the feedback mode of the SECM. Assignment of the process as a hole injection from the oxidized form of the redox couple into the valence band and assignment of the energy of the valence band edge in the semiconductor were made by studying the behavior of the feedback current at various pHs and with different redox couples. The nature of the dopant strongly affected the etching process. n-GaAs and undoped GaAs were etched by using the feedback mode while p-GaAs was completely resistive toward etching. The differences between n-GaAs and p-GaAs are explained in terms of semiconductor-electrolyte interactions. © 1990, American Chemical Society. All rights reserved.