Density-dependent electron transport for accurate modeling of AlGaN/GaN HEMTs

Summary form only given. We report on accurate modeling of GaN HEMTs for RF operation taking into account sheet charge density (n_s) dependence of electron velocity in 2-dimensional electron gases (2DEGs). Electron velocity characteristics of the channel directly impact DC and high frequency transistor performance, and it is critical to understand velocity at all charge density and field conditions to accurately predict large signal performance of GaN HEMTs. Previous models of AlGaN/GaN HEMTs have taken into account field dependence of electron velocity, but have not considered its dependence on channel sheet charge density [1]. In this work, we have directly measured velocity characteristics of 2DEGs as a function of field and sheet charge density, and used them to accurately simulate DC and small signal characteristics of GaN HEMTs. The work done here provides a method to accurately simulate DC and RF characteristics of GaN HEMTs over the entire bias range.