Model for conductance in dry-etch damaged <i>n</i>-GaAs structures

Abstract

A model for the effects of dry-etch damage on the conductances of etched structures is developed. Expressions for defect distribution are obtained for top-surface and sidewall damage. The expression for sidewall damage is used in the calculation of wire conductances. The model accounts accurately for changes in experimentally measured conductances of SiCl4-etched n+-GaAs wires with variations in material carrier concentration, epilayer thickness, and etch time/depth. The analysis indicates that defects are created at a significant rate at sidewalls as compared to top surfaces.