Design and simulation of a novel 1400 V–4000 V enhancement mode buried gate GaN HEMT for power applications

A novel enhancement mode structure, a buried gate gallium nitride (GaN) high electron mobility transistor (HEMT) with a breakdown voltage (BV) of 1400 V–4000 V for a source-to-drain spacing ( L SD ) of 6 μm–32 μm, is investigated using simulations by Silvaco Atlas. The simulations are based on meticulous calibration of a conventional lateral 1 μm gate length GaN HEMT with a source-to-drain spacing of 6 μm against its experimental transfer characteristics and BV. The specific on-resistance R S for the new power transistor with the source-to-drain spacing of 6 μm showing BV = 1400 V and the source-to-drain spacing of 8 μm showing BV = 1800 V is found to be 2.3 m Ω · cm 2 and 3.5 m Ω · cm 2 , respectively. Further improvement up to BV = 4000 V can be achieved by increasing the source-to-drain spacing to 32 μm with the specific on-resistance of R S = 35.5 m Ω · cm 2 . The leakage current in the proposed devices stays in the range of ∼5 × 10 −9 mA mm −1 .