The thermal effect on the output conductance in AlGaN/GaN HEMT's

The aim of this work is to study the potential offered by microwave power in the device AlGaN/GaN HEMT by studying the thermal effect and self heating on the output conductance taking into account the effects of spontaneous and piezoelectric polarization. We presented an analytical model for the concentration of electrons "n
_s
" in the 2DEG and the current I
_ds
in the channel of HEMT for strong inversion regime by solving the Poisson equation and Schrodinger self-consistent calculation. Thanks to the analytical description of the current I
_ds
we are able to demonstrate changes in the output conductance g
_d
according to the voltage V
_ds
, including the spontaneous and piezoelectric polarization, self heating and thermal effects on the HEMT drain conductance g
_d
. We noted that when the temperature increases, the electron mobility decreases, this is due to a deterioration of transport properties which is dominated by the scattering with phonons. This decrease in mobility leads to a drop in drain current therefore a degradation of electrical characteristics that determine performance of the transistor.