Etching temperature dependence of the surface composition and reconstruction for Cl2‐etched GaAs layers

In order to understand the mechanism of the Cl2‐etching reaction with GaAs, the composition and reconstruction of in situ Cl2‐etched GaAs surfaces were studied as functions of the etching temperature. From an Auger electron spectroscopy analysis and reflection high‐energy electron‐diffraction observations, it was shown that the GaAs surface changed from As stabilized to Ga stabilized during low‐temperature (∼50 °C) etching, while it remained As stabilized during high‐temperature (150–250 °C) etching. This result can be understood by considering the temperature dependence of the desorption rate of chloride compounds. At low temperature, the desorption of Ga chlorides is more suppressed than that of As chlorides, resulting in rough Ga‐stabilized surfaces. At high temperature, the desorption of any chlorides is not suppressed. Thus, stoichiometric etching is realized, resulting in smooth As‐stabilized surfaces, which are advantageous for high‐performance microdevice fabrication.