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

• AlGaN/GaN MOS-HEMT device having source connected field plate.
• 2D Sentaurus TCAD drift diffusion simulation model calibrated with experimental results.
• Analyzed the impact of varying Lgd and passivation thickness (tp) on breakdown voltage and drain current.
• High BV=752.8 V and Id=1.9 A/mm obtained by optimizing Lfp and tp.

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 (LgdLgd), source field plate length (LfpLfp) and passivation layer thickness (tptp) 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 LfpLfp and tptp. Very high breakdown voltage of 752.8 V is obtained by optimizing the Lfp to 3 µm and tptp to 200 nm at a fixed gate to drain distance of 3.4 µm. 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.

• Analysis of breakdown voltage is done varying the gate to drain distance (L_gd) , passivation layer thickness (t_p) and source field plate length (L_fp).
• High drain current (I_d)=1.9 mA/mm and breakdown voltage=752.8V obtained.Figure optionsDownload as PowerPoint slide