Suppression of Enhanced Magnesium Diffusion During High-Pressure Annealing of Implanted GaN

Abstract

Activation of ion-implanted p-type dopants in gallium nitride has demonstrated great progress utilizing high pressures to enable novel and traditional device architectures; however, such conditions consistently exhibit anomalously enhanced diffusion up to several microns in very short periods of time for device relevant concentrations. Here, this diffusion is shown to be modulated by unintentional hydrogen content within the anneal ambient and thus controllable by inclusion of a high-temperature hydrogen getter. Furthermore, diffusion is also shown to be greatly suppressed using co-implanted oxygen at low concentrations while simultaneously maintaining characteristics of p-type material in photoluminescence. Subsequently, after annealing at 1300 °C for 30 min in 3.8 kbar of nitrogen pressure, the magnesium concentration in the diffusion tail is suppressed by 28% at 1–1.5 μm in depth using a hydrogen getter alone, which reduces hydrogen uptake by 45% and fully suppressed at >1 μm in depth using co-implantation alone and further reduced with concurrent use of a hydrogen getter. Co-implantation alone reduces the in-diffused magnesium dose by 60% compared to reference samples.