2734 IEEE TRANSACTIONS ON NUCLEAR SCIENCE, VOL. 58, NO. 6, DECEMBER 2011 Single-Event Damages Caused by Heavy Ions Observed in AlGaN/GaN HEMTs Satoshi Kuboyama, Akifumi Maru, Hiroyuki Shindou, Naomi Ikeda, Toshio Hirao, Hiroshi Abe, and Takashi Tamura Abstract—It was demonstrated that several kinds of permanent damage were introduced by heavy ions in AlGaN/GaN HEMTs similar to SiC devices. A new mode of damage attributable to the transistor structure was also identified in addition to the damage observed similarly in SiC devices. Index Terms—AlGaN/GaN HEMTs, heavy ions, radiation damage, single-event effects. I. INTRODUCTION F OR advanced space telecommunication equipment, AlGaN/GaN High Electron Mobility Transistors (HEMTs) are very attractive because of their high efficiency and robustness to the harsh environment in space. Several prod- ucts for space applications are already available in the space industry market, the radiation response of which has already been extensively reported. However, most reports concern the displacement damage caused by protons and electrons [1]–[4] and there are few reports on Single-Event Effects (SEEs) [5]. The excellent performance of AlGaN/GaN HEMTs is attrib- utable to its wide band-gap feature of GaN and AlGaN materials and the band-gap engineering technique to make hetero-junc- tion structure. Another wide band-gap material, SiC, is also expected to be utilized for space applications in the near future and extensively studied. The first SiC devices that became available in the com- mercial market was power Schottky diodes, for which unex- pected incidents of single–event damage have been reported [6], [7], hence the mechanism of such damage remains improperly understood. There is a possibility that the mechanism is essen- tially related to the wide band-gap feature of the materials and also observed in AlGaN/GaN devices. In this study, AlGaN/GaN HEMT devices were irradiated with heavy ions from an accelerator and a detailed response, such as collected charge, was measured to characterize their susceptibility to SEEs. As a result, several kinds of damage Manuscript received July 22, 2011; revised September 14, 2011; accepted September 29, 2011. Date of publication November 11, 2011; date of current version December 14, 2011. S. Kuboyama, A. Maru, H. Shindou, N. Ikeda, and T. Tamura are with the Japan Aerospace Exploration Agency, Tsukuba, Ibaraki, 305-8505 Japan (e-mail: kuboyama.satoshi@jaxa.jp). T. Hirao, and H. Abe are with the Japan Atomic Energy Agency, Takasaki, Gunma 370-1292 Japan (e-mail: hirao.toshio@jaea.go.jp). Color versions of one or more of the figures in this paper are available online at http://ieeexplore.ieee.org. Digital Object Identifier 10.1109/TNS.2011.2171504 TABLE I MAJOR PARAMETERS OF SAMPLE NGa HEMT were observed. Most of the damage was similar to that ob- served in SiC diodes. In addition to this damage, an additional damage mode, involving leakage paths emerging between the drain and source terminals without any damage signature to the gate, was identified in GaN HEMT devices. The new damage mode was discussed and a preliminary device simulation to model the damage was performed. II. EXPERIMENTAL A. Sample Devices Two types of AlGaN/GaN HEMTs from two different manufacturers were used in this study. The first one was EGNB004ME from Sumitomo Electric Device Innovations, Inc. (SEDI) in Japan, which was intended for space applications and identified as device type “A” in this study. An additional device type “B” was also used as another reference sample. It was commercially available and intended for commercial applications. No special structure to improve the vulnerability to the radiation environment was employed for either type of device. Their maximum ratings and electrical parameters are as shown in Table I. The cross-sectional structure of the device is similar to that already published [4], however detailed design parameters are proprietary information of the manufacturers and were not available for this study. 0018-9499/$26.00 © 2011 IEEE