Monte Carlo Investigation of High-Field Electron Transport Properties in AlGaN/GaN HFETs
Mingyan Wang, Yuanjie Lv, Zuokai Wen, Heng Zhou, Peng Cui, Zhaojun Lin
Abstract
This letter analyzes the velocity-field relationship of AlGaN/GaN HFETs via Monte Carlo simulation. This method is based on complete scattering mechanisms such as polarized coulomb field scattering (PCF scattering), polar optical phonon scattering, acoustic deformation potential scattering, inter-valley phonon scattering, and piezoelectric scattering. It is found that the gate bias voltage affects the PCF scattering intensity and the PCF scattering intensity influences the drift velocity under a high electric field. A decrease in peak steady-state drift velocity is observed for our fabricated AlGaN/GaN HFETs from <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${1.335}\times {10}^{{5}}$ </tex-math></inline-formula> m/s at <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{V}_{\text {gs}} =$ </tex-math></inline-formula> 0 V to <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${1.23}\times {10}^{{5}}$ </tex-math></inline-formula> m/s at <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{V}_{\text {gs}} =-3$ </tex-math></inline-formula> V as the gate voltage becomes more negative. When combined with the velocity-field relationship obtained from Monte Carlo simulations, the calculated current-voltage characteristics of AlGaN/GaN HFET devices are in good agreement with our experiment results. The electron saturation drift velocity deviation of AlGaN/GaN HFETs from the Monte Carlo simulation of the GaN material is attributed to the presence of PCF scattering in AlGaN/GaN HFETs. In the study, we provide strong support for the accurate modeling of AlGaN/GaN HFETs.