To utilize the great potential of nitride compound semiconductors and improve their characteristics for a variety of high power applications, physical theories describing the device performance and reliability are needed. In this vein we provide noise-based reliability indicators through the quantum theory of 1/f noise. We develop new physical theories of FET and HFET failure based on the new concept of "heat instability." This allows suggesting stability criteria and new approaches to increase the reliability of HFETs. The quantum 1/f noise formulas have been recently refined for the case of AlGaN/GaN HFETs, of other heterostructures and FETs through a better definition of the coherence parameter s, exhibiting much better agreement with the experiment. This allows for the first time to verify the reliability of a device by comparing the measured 1/f noise with its calculated value. Furthermore, quantum theory based studies of the noise behavior of FETs and HFETs under the influence of ionizing radiation induced damage, allow development of measures for radiation hardening. They also clarify the failure mechanisms and suggest ways to reliability optimization for rf stress. Results reported for the first time in this paper show that under certain conditions, limited doses of radiation may improve HFETs and reduce their channel 1/f noise. This happens by reduction of (large angle) lattice scattering in favor of (small angle) defect and impurity scattering. The theory also predicts that the noise of p-n junction-based devices will always increase. Finally, the new quantum 1/f noise methods developed here are applied to compound semiconductor MQW infrared and THz photodetector heterostructures.

Date Published: 15 February 2008
PDF: 13 pages
Proc. SPIE 6894, Gallium Nitride Materials and Devices III, 68941K (15 February 2008); doi: 10.1117/12.764083

Published in SPIE Proceedings Vol. 6894:
Gallium Nitride Materials and Devices III
Hadis Morkoç; Cole W. Litton; Jen-Inn Chyi; Yasushi Nanishi; Euijoon Yoon, Editor(s)