Modeling And Optimization Of High Electron Mobility Transistor (HEMT)

Solid state semiconductor devices,expecially HEMT, have received much attention in recent years for high power, high-frequency microwave power amplifications,in which vacuum tube devices have long been dominating. HEMT is a promising candidate for high frequency, high power,high breakdown voltages,high signal-to-noise ratio, high temperature- and high-frequency operation.This paper focuses on modeling,simulation and optimization on HEMT from device structure,polarization effects,AC and DC characteristics aspects.ISE-TCAD software has been use in this paper to bulid AlGaN/GaN HEMT simulation model, combined with proper assignment of GaN,AlN and AlGaN material parameters. The built model also sets up all kinds of physical equations and physical models, includ Poisson equation, continuity equations, carrier statistics model (Fermi-Dirac statistics), transport models (hydrodynamic model) and recombination model (Shockley-Read-Hall).The AlGaN/GaN HEMT model is simulated in the areas of device structure, charge distribution, current characteristics and microwave performance. The simulation results get the relationship among the band structure, two dimension electron gas (2DEG) density transfer and output characteristics. Comparing the simulations results with experimental results in the references, the values and trend are basicly similar and this demonstrates the correctness of the built HEMT model.Optimization of AlGaN/GaN HEMT is focused on polarization charge density, donor surface traps at the AlGaN interface, contact resistance, AlGaN thickness and source-to-gate spacing. Optimization results show a great improvement on drain current, transconductance and threshold voltage.The HMET model is setted up in this paper.The simulation and optimization work of the proposed mode is finished after it. Some helpful method and conclusion are derived for the performance improvmentation of HEMT devices. The further researches that can be carried out based on the proposed work are making use of a more accurate account of the polarization and hot electron effects.