Title :
Total-Ionizing-Dose Radiation Effects in AlGaN/GaN HEMTs and MOS-HEMTs
Author :
Xiao Sun ; Saadat, Omair I. ; Jin Chen ; Zhang, E.X. ; Cui, Shuguang ; Palacios, T. ; Fleetwood, D.M. ; Ma, T.P.
Author_Institution :
Electr. Eng. Dept., Yale Univ., New Haven, CT, USA
Abstract :
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 (Vth) shifts have been revealed: a rapid Vth shift at low doses for both HEMTs and MOS-HEMTs, and an additional Vth shift only found in MOS-HEMTs for doses up to at least 2 Mrad (SiO2). The rapid Vth shift anneals quickly and is a strong function of layer material. We attribute this portion of the Vth shift to hole trapping in the AlGaN barrier layer. The Vth shift at high doses found only in MOS-HEMTs is attributed to hole trapping in the gate oxide. By comparing MOSFETs with HfO2 and Al2O3 gate dielectrics that are annealed during processing at various temperatures, we find that 500°C annealed HfO2 shows the most promising TID response.
Keywords :
III-V semiconductors; aluminium compounds; annealing; gallium compounds; hafnium compounds; high electron mobility transistors; wide band gap semiconductors; Al2O3; AlGaN-GaN; HfO2; MOS-HEMT; SiO2; TID radiation effect; TID response; X-ray irradiation; annealing; barrier layer; dose function; electron volt energy 10 keV; gate dielectrics; gate oxide; hole trapping; layer material; radiation bias; threshold voltage; total-ionizing-dose radiation effect; voltage shift; Aluminum gallium nitride; Aluminum oxide; Annealing; Gallium nitride; HEMTs; Hafnium oxide; MOSFET; Radiation effects; ${rm Al}_{2}{rm O}_{3}$; ${rm HfO}_{2}$; ALGaN; GaN; HEMT; MOS; annealing; charge trapping; radiation; total ionizing dose;
Journal_Title :
Nuclear Science, IEEE Transactions on
DOI :
10.1109/TNS.2013.2278314
