Novel high-voltage GaN CAVET with high threshold voltage and low reverse conduction loss.

A novel GaN current-aperture vertical electron transistor (CAVET) with an energy band pinning (EBP) structure (EBP-CAVET) is proposed and investigated by simulations. The EBP-CAVET is featured with hybrid contacts on the p-GaN layer, locally having Ohmic contact combined with Schottky gate metals in the longitudinal direction. The Ohmic contact is shorted to the source electrode and the Schottky gate metals are shorted to the gate electrode. The conduction band (E c) in the gate region is modulated by the alternately arranged contacts. In the Ohmic contact region, E c remains a fixed value, which acts as an energy band pinning and suppresses the variation of the E c in the gate region. In the on-state (V GS > 0 V) and blocking-state with high V DS , the EBP structure inhibits the E c shifting downwards in the gate region to achieve a high threshold voltage (V th), a low leakage current density (J dss), and a high breakdown voltage (BV). In the reverse conduction state (V DS < 0 V & V GS ≤ 0 V), the EBP structure suppresses the E c shifting upwards to achieve a low and independent of gate bias reverse turn-on voltage (V RT). The proposed EBP-CAVET achieves a high V th of 2.10 V, a V RT of 0.69 V, a low J dss of 3.1 × 10−11 A/cm2 at V DS = 1000 V, a high BV of 1660 V. Compared with an integrated Schottky barrier diode or fin diode in a field effect transistor (FET), the EBP structure occupies a much smaller chip area. Thus, the EBP-CAVET achieves a low specific ON-resistance (R on,sp) of 1.19 mΩ cm2 and an extremely high power-figure-of-merit (PFOM) up to 2.32 GW/cm2. Consequently, the proposed structure presents a new design concept and enhances the application potential for GaN CAVET with high V th and low reverse conduction loss. • A novel GaN CAVET with an energy band pinning structure (EBP-CAVET) is proposed to improve the forward characteristic and reverse conduction characteristic. • In the reverse conduction (V SD > 0V, V GS ≤ 0V),the EBP-CAVET realizes a low V RT and the V RT is independent of V GS. • The proposed EBP-CAVET achieves a high V th of 2.10 V, a lower J dss of 3.1 × 10−11 A/cm2, and a higher BV of 1660 V. • Since the EBP structure occupies a minimal chip area, the EBP-CAVET achieves a low R on,sp of 1.19 mΩ cm2 and an extremely high PFOM up to 2.32 GW/cm2. [ABSTRACT FROM AUTHOR]