To understand the effects of 60Co gamma-irradiation, systematic studies were carried out on n-channel AlGaN/GaN high electron mobility transistors. Electrical testing, combined with electron beam-induced current measurements, was able to provide critical information on defects induced in the material as a result of gamma-irradiation. It was shown that at low gamma-irradiation doses, the minority carrier diffusion length in AlGaN/GaN exhibits an increase up to ∼300Gy. The observed effect is due to longer minority carrier (hole) life time in the material's valence band as a result of an internal electron irradiation by Compton electrons. However, for larger doses of gamma irradiation (above 400Gy), deteriorations in transport properties and device characteristics were observed. This is consistent with the higher density of deep traps in the material's forbidden gap induced by a larger dose of gamma-irradiation. Moderate annealing of device structures at 200°C for 25min resulted in partial recovery of transport properties and device performance.
|Number of pages||9|
|Journal||Radiation Effects and Defects in Solids|
|State||Published - 4 May 2015|
Bibliographical noteFunding Information:
UCF and WIS research was partially supported by NATO SfP award # 9844662. The work performed at UF is supported by an U.S. DOD HDTRA Grant No. 1-11-1-0020, monitored by Dr. James Reed.
© 2015 © 2015 Taylor & Francis.
- Activation energy
- Diffusion length
- Gamma irradiation
- High electron mobility transistors
- Wide-band-gap semiconductors