Nitride based high power devices: design and fabrication issues

Abstract

We have modeled the breakdown voltage, critical current density and maximum operating frequency of several nitride based high power and high temperature electronic devices. It is found that the minority carrier recombination lifetime and the critical field for electric breakdown are important model parameters which influence device design and performance. Planar geometry GaN Schottky devices were fabricated and used to experimentally estimate these important parameters. Current–voltage measurements have indicated the importance of the non-planar geometries for achieving large breakdown voltages. The minority carrier (hole) diffusion length and recombination lifetime have been measured using the electron beam induced current technique. The measured hole lifetime of 7 ns and estimate for the critical field indicate the possibility of AlGaN based thyristor switch devices operating at 5 kV with current densities up to 200 A/cm 2 and at frequency above 2 MHz. The GaN structural and optical material quality as well as processing requirements for etching are also discussed.