Improvement of reverse conduction characteristic and single event effect for a novel vertical GaN field effect transistor with an integrated MOS-channel diode

Abstract

A vertical GaN-based field-effect transistor with an integrated MOS-channel diode (MCD) is used to improve the reverse conduction characteristic and transient single-event effect (SEE). The device features an MCD acting as a free-wheel diode formed between trench source metal on the source dielectric and a P-type blocking layer (PBL), wherein MIS structure is formed by trench source, source dielectric and N-drift. At the reverse conduction (VSD > 0 V, VGS ≤ 0 V), because the channel between the PBL and the MIS structure is opened, the MCD turns on to realize a low reverse turn-on voltage (VRT) and the VRT is independent of VGS. At the forward conduction (VDS > 0, VGS > Vth), the MCD is pinched-off without influencing the on-state characteristic of the MCD-FET. Moreover, owing to the modulation effect of the PBL on electric-field distribution, both the impact ionization rate and transient SEE peak current (Ipeak) is reduced. Consequently, a low VRT = 0.67 V, low Ipeak = 10.11 mA and high BV = 1573 V are achieved. The VRT and Ipeak are decreased by 46.4 % and 64.9 %, respectively, compared with those of the conventional current aperture vertical electron transistor (CAVET).