Impact of a drain field plate on the breakdown characteristics of AlInN/GaN MOSHEMT

Abstract

In this paper, a novel AlInN/GaN metal oxide semiconductor high electron mobility transistor (MOSHEMT) employing the drain field plate technique is proposed and the effect of a drain field plate on the breakdown voltage (BV) is investigated. A reduction of the peak electric field is required to achieve AlInN/GaN MOSHEMTs with a high BV. The proposed AlInN/GaN MOSHEMT with both gate and drain field plates simultaneously reduces the electric field concentration at the gate and the drain edge by decreasing the potential gradient along the channel for the 2 dimensional electron gas (2DEG). The reduction in the peak electric field at the drain edge of the proposed device leads to a 57% increase in BV compared with the BV for an AlInN/GaN MOSHEMT with a gate field plate only. A significantly higher BV can be achieved by optimizing the gate-to-drain distance (Lgd), the length of the drain field plate (Ldfp) and the thickness of the SiN passivation layer thickness (TSiN). A detailed breakdown analysis of the device was carried out using Silvaco Technology Computer Aided Design (TCAD). The detailed numerical simulations were done by using the non-local energy balance (EB) transport model, which was calibrated with the previously published experimental results. The results showed a great potential for applications of the drain-field-plated AlInN/GaN MOSHEMT to deliver high currents and high powers in microwave technologies.