Gold diffusion in InP

Abstract

InP device degradations have often been related to the presence in the active layer of gold atoms having migrated from the contacts. We have studied gold thermal diffusion in InP in the temperature range 400–700 °C, using secondary ion mass spectrometry (SIMS). We have pointed out SIMS artifacts and how to avoid them. We have found small values for the diffusion coefficient: 2×10−12 cm2/s at 550 °C. By deep-level transient spectroscopy measurements, gold appeared to behave as a shallow donor, with a level situated at 0.55 eV from the conduction band. Our conclusion is that gold thermal migration from the contact is not the mechanism responsible for the device degradation.