Estimation of polarization charge in nitride based MODFETs using differential threshold voltage technique

Abstract

We propose a novel method to estimate net polarization charge of nitride-based Modulation-doped Field Effect Transistors (MODFETs) introducing the concept of differential threshold voltage. We simulate MODFET device using an in-house built self-consistent Poisson-Schrodinger solver and calculate net polarization charge present in the device that can be efficiently used for improving device performance. Polarization increases electron charge density and consequently improves device speed and current. In this paper, we show the simulated results of AlGaN/GaN MODFET as an example and verify the accuracy of our charge calculation procedure by comparing our results with related works. Accurate knowledge of net polarization charge using the proposed estimation technique would provide better control of device characteristics.