Optical activation and diffusivity of ion-implanted Zn acceptors in GaN under high-pressure, high-temperature annealing

Abstract

Optical activation of Zn ions implanted to an epitaxial film of GaN was performed by means of sample annealing at N2 overpressure up to 1.6 GPa. By applying pressure we avoided GaN decomposition and could increase the annealing temperature up to 1550 °C versus a limit of 1000-100 °C at ambient pressure. The Zn-acceptor-related photoluminescence (PL) intensity in implanted samples is maximized by annealing above 1350 °C after which the Zn PL intensity exceeds epitaxially doped GaN:Zn with comparable Zn concentration by factor 15. High-pressure annealing causes a significant diffusion of implanted Zn atoms in GaN films. It is also possible to diffuse Zn from the external source into the implanted/unimplanted layers. High dislocation densities strongly accelarate the Zn diffusion. © 1998 American Institute of Physics.