Analytical model to evaluate threshold voltage of GaN based HEMT involving nanoscale material parameters

Abstract

In this paper, an improved analytical model involving nanoscale materials parameters for predicting threshold voltage of GaN HEMT is proposed. The proposed model for the first time incorporates the effect of structural miniaturization on nanoscale parameters such as bandgap, melting temperature, permittivity and polarization on the threshold voltage. The proposed model is derived, maintaining the charge neutrality across the device. Additionally, the effect of strain relaxation on threshold voltage due to higher Al mole concentration is included in the model. The surface barrier height is also evaluated as a considering both Al mole concentration and AlGaN barrier layer thickness. The developed model is verified for various topologies of HEMT exhibiting tunability and demonstrating excellent agreement between evaluated values and extracted values from the experimental data. • Proposed model considers nanoscale materials parameters to predict threshold voltage of different GaN HEMTs. • The effect of strain relaxation on threshold voltage due to higher Al mole concentration is considered in the model. • The surface barrier height is evaluated considering different Al mole concentration and AlGaN barrier layer thickness. • The developed model is validated for various topologies of HEMTs demonstrating excellent agreement with experimental data.