Surface composition and etching of III-V semiconductors in Cl2 ion beams

Abstract

Surface composition and etching of InP and GaAs in Cl₂ ion beams was investigated. In situ analysis of the substrate using Auger electron spectroscopy demonstrated selective removal of phosphorous from InP leaving a thin (⩽50 Å) surface layer enriched with In after etching at room temperature with a 500‐eV Cl⁺/Cl⁺₂ beam. GaAs does not show selective removal of the group V element, resulting in no significant change in surface composition after etching. These results reflect the involatility of the In chlorides at room temperature. Etch rate results indicate that at low ion energy (200 eV) or high neutral reactant flux, removal of the group III chloride from the surface is rate limiting. At high ion energy (500 eV) and low neutral flux, supply of reactant to the surface is rate limiting.