Local stress engineering for the optimization of p-GaN gate HEMTs power devices

摘要

The impact of the built-in stress of the SiN passivation layer on p-GaN gate High Electron Mobility transistors (HEMTs) is investigated through TCAD simulations. Local modifications of electron confinement in the channel area due to stressor deposition can be exploited to increase the threshold voltage independently of the ON-state resistance (up to +1.5 V for t_siN = 200 nm, σ_sin = -2GPa and L_G = 0.2 μm). This technique can also be easily combined with an AlGaN back- barrier structure to increase the design margin of p-GaN gate normally-OFF HEMTs.