Abstract:
During the past few decades, immense progress has been made in the development of group
III (Ga) – N based devices. GaN-based RF power devices have made substantial progresses due to its
potential in high operation voltage, high output power density and high input impedance, which is
due to high sheet charge density, high breakdown field and high electron saturation velocity.
This work presents an AlGaN/GaN high electron mobility field effect transistor (HEMT)
nonlinear model incorporating polarization fields induced by strain at the heterojunction of HEMT.
Experimental work done in AlGaN/GaN HEMT has shown that the polarization charges are
nonlinear function of the composition of AlGaN/GaN HEMT. Polarization fields induced by strain
greatly affect the properties and behavior of AlGaN/GaN HEMT.
This work provides AlGaN/GaN
HEMT model that includes a nonlinear approximation of the polarization charges at interface of the
device. The effect of strain relaxation on the sheet carrier density and threshold voltage for different
mole fraction of Aluminum in barrier layer and its thickness is also presented.
