The low-temperature catalyzed etching of gallium arsenide with hydrogen chloride

Abstract

A heated tungsten filament has been used to catalyze the gas phase etching of gallium arsenide with hydrogen chloride at a substrate temperature of 563 K. Rapid etch rates, between 1 and 3 microns per minute, were obtained in a pure hydrogen chloride ambient in the pressure range of 3.3 to 20.0 Pascal. Low flow rates of hydrogen quenched the etching reaction, and resulted in degradation of the quality of the etched gallium arsenide surface. Dilution of the hydrogen chloride to 10.5% in helium reduced the etch rate to 63 nanometers per minute. The removal of 83 nm of gallium arsenide with the helium-diluted gas mixture resulted in a specular surface. X-ray photoelectron spectroscopy indicated that the gallium arsenide surface became enriched in gallium after the etch in helium-diluted hydrogen chloride. No tungsten or other metal contamination on the etched gallium arsenide surface was detected by x-ray photoelectron spectroscopy.