Study of HfAlO/AlGaN/GaN MOS-HEMT with source field plate structure for improved breakdown voltage

In the present paper, we propose a novel device structure by introducing a source field-plated AlGaN/GaN in the metal oxide Semiconductor high electron mobility transistors (MOS-HEMT) structure having a relatively short gate length and short gate-to-drain distances. The 2D breakdown analysis is performed using Sentaurus TCAD simulator. The effects of gate to drain distance (L-gd), source field plate length (L-fp) and passivation layer thickness (t(p)) on breakdown voltage (BV) is analyzed. The simulations are done using the drift-diffusion (DD) model, which is calibrated/validated with the previously published experimental results. The breakdown voltage is observed to increase with increase in L-fp and t(p). Very high breakdown voltage of 752.8 V is obtained by optimizing the L-fp to 3 mu M and t(p) to 200 nm at a fixed gate to drain distance of 3.4 mu m. The results show a great potential application of the ultra-thin HfAlO source field plated AlGaN/GaN MOS-HEMT to deliver high currents and power densities in high power microwave technologies. (C) 2014 Elsevier B.V. All rights reserved.