Effect of AlN spacer thickness on device characteristics of AlInN/AlN/GaN MOSHEMT

Abstract

In this paper the effect of binary AlN spacer thickness on device performance of 30 nm gate length lattice matched Al 0.83 In 0.17 N/AlN/GaN MOSHEMT (Metal Oxide Semiconductor High Electron Mobility Transistor) is investigated using Atlas simulations. The numerical simulations are done using non local energy balance (EB) transport models. We have optimized the binary spacer thickness for obtaining the enhanced device performance. The main findings of this report indicates the increase in 2DEG (2 Dimensional Electron Gas) density when a binary AlN spacer layer is inserted at the interface of AlInN/GaN owing to enhanced conduction band offset and high polarization field. The maximum drain current of 1.1 A/mm is achieved at 1.4 nm AlN spacer thickness due to high 2DEG sheet charge density and mobility. Insertion of AlN spacer layer also reduces the reverse Schottky gate leakage current of the order of 10−6A/mm. Optimization of AlN spacer thickness makes the proposed device suitable for high power and high frequency electronic applications.