Electron transport analysis of 4H-SiC with full-band Monte Carlo simulation including real-space Coulomb interactions

Abstract

4H-SiC has been widely used in many applications. All of these benefit from its extremely high critical electric field with good electron mobility. 4H-SiC possesses a critical field ten times higher than that of Si, which allows high-voltage blocking layers composed of 4H-SiC to be approximately a tenth the thickness of a comparable Si device, thus reducing the device on-resistance and power losses, while maintaining the same high blocking capability. Unfortunately, commercial Technology for Computer-Aided Design tools like Sentaurus and Silvaco Atlas are based on effective mass approximation, while most 4H-SiC devices are not operated under a low electric field so the parabolic-like band approximation does not hold anymore. Hence, to get more accurate and reliable simulation results, full-band analysis is needed. The first step in the development of a full-band device simulator is the calculation of the band structure. In this work, the empirical pseudopotential method is adopted. The next task in the sequence is the calculation of the scattering rates. Acoustic, non-polar optical phonon, polar optical phonon, and Coulomb scattering are considered. Coulomb scattering is treated in real space using the particle–particle–particle–mesh approach. The third task is coupling the bulk full-band solver with a 3D Poisson equation solver to generate a full-band device simulator. For proof-of-concept of the methodology adopted here and for simplicity, a 3D resistor is simulated. From the resistor simulations, the low-field electron mobility dependence upon Coulomb scattering in 4H-SiC devices is extracted. The simulated low-field mobility results are in excellent agreement with available experimental data.