in order to understand the mechanism of the Cl-2-etching reaction with GaAs, the composition and reconstruction of in situ Cl-2-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 eras shown that the GaAs surface changed from As stabilized to Ga stabilized during low-temperature (similar to 50 degrees C) etching, while it remained As stabilized during high-temperature (150-250 degrees 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 recited resulting in smooth As-stabilized surfaces, which are advantageous for high-performance microdevice fabrication.