Source of Ge centers in AlGaAs grown by organometallic vapor phase epitaxy and the effect of impurity getters

摘要

A long term and comprehensive study has been performed to identify the origin of the Ge center in AlGaAs grown by organometallic vapor phase epitaxy. With a series of deductive investigations, AsH3gas has been undoubtedly identified as the source of the Ge contamination. Depending on the AsH3quality, one to two orders of magnitude of difference in Ge trap densities has been observed. Longhyphen;term observations indicate fairly constant Ge content throughout most of the AsH3tank lifetime. Different impurity getters were attempted to remove the Ge contaminant. While most getters can eliminate the oxygenhyphen;related defects in AlGaAs, no getters were able to remove the Ge DX center. copy;1996 American Institute of Physics.