Radiation hardness of AlGaN/GaN based HEMTs

Abstract

In this work we present steady-state characteristics and low-frequency noise spectra of AlGaN/GaN based high electron mobility transistors (HEMTs) exposed to gamma ray radiation. The devices with a variety of gate length (150-350 nm) and width (100-400 νm) were irradiated by 60Co gamma rays with doses in the range of 104-109 Rad and flux of 102 Rad/s. Dose dependencies of basic operating parameters of the transistors, such as saturation current (Isat), transconductance (gm), channel conductance (gc), and threshold voltage (VT) are analysed. Our study show that visible changes of above mentioned parameters are observed under relatively small doses (105 Rad) and strongly depend on the HEMT's topology. The transconductance decreases and threshold voltage becomes more negative for all devices while deviation of these parameters from its initial values does not exceed 20% at highest irradiation dose. At the same time variation of the channel conductance as well as saturation current depends to a high extent on the gate voltage (Vg). At |Vg| < |Vcr|, both Isat and gc show a reversal proportional to the cumulative dosage of radiation. However, at |Vg| > |Vcr|, drain saturation current and channel conductance increase with the cumulative dosage of radiation. The effect is more pronounced in short-length-gate devices.

Enhancement of Electrical Parameters of Ni/n-GaN SBDs under Remote and not In-flux Gamma Irradiation

“…24,25 Some studies have been conducted on GaN devices' reliability and radiation hardness, particularly for high gamma-irradiation doses. 19,[26][27][28] The present study reports the dose-dependent modifications in Ni/n-GaN SBDs electrical properties that were irradiated by remote and non-in-flux gamma rays 18,29 at cumulative doses of between 250 Gy to 1 kGy. Experimental 4 μm thick epitaxial, Si-doped GaN layer grown on polished sapphire (0001) was used to fabricate Ni/n-GaN SBDs.…”

60 Co gamma radiation effect on AlGaN/AlN/GaN HEMT devices

“…More recently, researchers have been focusing on the study of the device performance degradation by gamma, proton, neutron and electron radiation on AlGaN/GaN HEMTs [3][4][5][6][7][8][9][10][11][12][13][14]. In 2002, Vituserich et al [15] of Cornell University reported the influence of γ-ray irradiation on the device performance of AlGaN/GaN HEMTs, and found that when the radiation dose was relatively low at 10 5 rad(Si), the device parameters showed significant changes: the transconductance was reduced and the threshold voltage was changed to negative. Fan et al [16] reported that at 300 Mrad, the influence was induced by 60 Co γ-ray irradiation on two-dimensional electron gas (2DEG) transport properties in AlGaN/GaN HEMTs, and considered that the device degradation was mainly due to the radiation induced heterojunction interface state charge.…”