Theoretical Study of Electron Transport Properties in GaN-Based HEMTs Using a Deterministic Multi-Subband Boltzmann Transport Equation Solver

A high-electron mobility transistor (HEMT) with a GaN channel is simulated using a deterministic multi-subband Boltzmann transport equation solver. A structure that includes an InGaN back barrier is considered. The electron mobility is calculated for the 1-D heterostructure to identify the contribution of each scattering mechanism to the electron mobility. For GaN-based HEMTs, electron transport in a non-equilibrium state is determined by solving the multi-subband Boltzmann equation expanded with Fourier harmonics. The polar optical phonon and the deformation potential phonon are considered to explain the scattering of the device while considering the Pauli principle. The results of a simulation conducted to assess the mobility and I-V characteristics are compared with experimental results from the AlInN/AlN/GaN/InGaN HEMT structure. The cutoff frequency of the HEMT is also estimated under the quasi-static approximation.