Total-Ionizing-Dose Radiation Effects in AlGaN/GaN HEMTs and MOS-HEMTs

• Published in: IEEE transactions on nuclear science 2013-12, Vol.60 (6), p.4074-4079
• Main Authors: Xiao Sun, Saadat, Omair I., Jin Chen, Zhang, E. Xia, Cui, Sharon, Palacios, Tomas, Fleetwood, Dan M., Ma, T. P.
• Format: Article
• Language: English
• Subjects: ALGaN; Aluminum gallium nitride; Aluminum gallium nitrides; Aluminum oxide; Annealing; charge trapping; Field programmable gate arrays; Gallium nitride; Gallium nitrides; GaN; Gates; Hafnium oxide; HEMT; HEMTs; High electron mobility transistors; MOS; MOSFET; radiation; Radiation effects; Semiconductor devices; Silicon dioxide; total ionizing dose; Trapping; {\rm Al}_{2}{\rm O}_{3}; {\rm HfO}_{2}
• ISSN: 0018-9499; 1558-1578
• DOI: 10.1109/TNS.2013.2278314

We have investigated the total ionizing dose (TID) radiation effects in AlGaN/GaN MOS-HEMTs as a function of dose and radiation bias, and compared them with conventional HEMTs. Under 10 keV X-ray irradiation, two distinct regimes of threshold voltage (V th ) shifts have been revealed: a rapid V th shift at low doses for both HEMTs and MOS-HEMTs, and an additional V th shift only found in MOS-HEMTs for doses up to at least 2 Mrad (SiO 2 ). The rapid V th shift anneals quickly and is a strong function of layer material. We attribute this portion of the V th shift to hole trapping in the AlGaN barrier layer. The V th shift at high doses found only in MOS-HEMTs is attributed to hole trapping in the gate oxide. By comparing MOSFETs with HfO 2 and Al 2 O 3 gate dielectrics that are annealed during processing at various temperatures, we find that 500 ° C annealed HfO 2 shows the most promising TID response.