Current Collapse Phenomenon in GaN HFETs resulting from Intentional Bulk Iron (Fe) Doping and Un-intentional Interface Traps

Introduction

The Gallium Nitride-based material family has fundamental material properties which make it an attractive candidate for semiconductor device fabrication.

These properties include:

1. High saturation velocities and breakdown field strength
2. Direct bandgap, allowing fabrication of light emitting devices
3. The ability to form hetero-structures using aluminum or indium
4. Large bandgaps allowing high temperature operation

Another stand-out feature of GaN based materials are their very high levels of spontaneous and strain induced piezo-electric charge. This material feature, however, has both advantages and disadvantages.