1/f Noise in GaN HEMTs grown under Ga-rich, N-rich, and NH3-rich conditions

The magnitude of the low-frequency 1/f noise in GaN/AlGaN HEMTs grown under Ga-rich, N-rich, and NH3-rich conditions varies in response to hot-electron stress. Density-functional-theory (DFT) calculations show that the Ga vacancies that are responsible for the positive shift in pinch-off voltage due to electrical stress in Ga-rich and N-rich devices do not contribute significantly to the observed changes in 1/f noise with electrical stress. The N anti-sites that cause negative shifts in pinch-off voltage in ammonia-rich devices can cause an increase in the noise magnitude after stress. DFT calculations also show that singly hydrogenated and dehydrogenated Ga-N divacancies also can contribute to the noise before and after stress, respectively. A decrease in noise magnitude is also observed in some devices after stress. © 2010 Elsevier Ltd. All rights reserved.

Duke Scholars

Author Tania Roy Electrical and Computer Engineering