Analysis Of The Reliability Of Passivation Layer And Interface Charge On Breakdown Voltage of E-Mode AlGaN/GaN MISHEMTs Device

Numerical simulations have been used to investigate how the breakdown and drain leakage current of E-Mode AlGaN/GaN MISHEMTs is influenced by the thickness and permittivity of the passivation layer. It is noticed that Breakdown Voltage (BV) and Drain Leakage are greatly influenced by the product of permittivity and passivation layer thickness. AlGaN/GaN MISHFETs with higher permittivity values and thicker passivation layers have been shown to have an electric field distribution in the channel. As a result, it is possible to effectively minimize the avalanche multiplication effect at high VDS and significantly enhance the Breakdown Voltage. With a 900 nm TiO2/15 nm HfO2 passivation stack, the device's Breakdown Voltage rises from 600 V to 1270 V when compared to an AlGaN/GaN MISHEMT without any top passivation layer. However, the combination method (Interface charge + permittivity + thickness of the passivation layer) has revealed the device's reliability because it enhances the Breakdown Voltage around 1370V. Subsequently, GaN MISHEMT devices with a passivation layer and interface charge demonstrated transconductance (GM) of 780 mS/mm and better ID Vs VDS characteristics curve as compared to GaN MISHEMT devices without passivation layer and interface charge.