# A Simulator for Investigation of Breakdown Characteristics of SiC MOSFETs
## 2 Simulation Method and Validation
### Validation  
The vertical diffused SiC MOSFET (VDMOSFET), shown in Figure 2, has excellent performance and is widely used. To verify and calibrate the simulator, we compared the output characteristics of VDMOSFET with those obtained from the experimental measurement [33]. The structure parameters are listed in Table 1, where * represents parameters for verifying the experimental result and # represents parameters for other simulations. It should be noticed that the doping profile within the base region is assumed to be a Gaussian distribution with a peak doping concentration of \(5\times 10^{16}\) cm\({}^{3}\). While performing the simulations, the Masetti mobility model, surface degradation mobility and high-field saturation mobility model, Auger recombination, impact ionization incomplete ionization and bandgap narrowing are used. Figure 3 presents comparisons for the VDMOSFET, with the output characteristics at T = 300 K for Vgs changing from 7 V to 10 V, and the transfer characteristics at a Vds of 10 V. As shown in Figure 3a, when Vgs is low, good agreement is achieved, while Vgs = 10 V, the ON-current are consistent with the experimental result. The difference in the saturation region is due to the limitations of existing physical models, especially high-field transport  
Figure 2: Schematic cross-section of the 4H-SiC VDMOSFET used for the simulation. Green represents N-type doping, yellow represents P-type doping, and shades of color represent heavy and light doping. Brown for oxide and gray for contact. models. Figure 3b shows that the results achieved good agreement. The model parameters used in the simulator are listed in Table 2.  
The simulation results are also verified by the commercial TCAD tool [35] for the detail distribution. The TCAD simulation utilized the same physical model as the simulator described above. For this simulation task, which involves nearly 6000 mesh points, our simulator, running on CentOS 7, requires roughly 200 MB of memory and completes the process in about three minutes on an Intel(r) (Santa Clara, CA, USA) Xeon(r) Gold 5218 Processor. Figure 4 shows the simulation results of the 4H-SiC VDMOSFET using this simulator, where the potential distribution is at x = 20 \(\upmu\)m in the vertical junction line between P Base \begin{table}
\begin{tabular}{c c c} \hline \hline
**Parameter** & **Value** & **Value** \\ \hline \hline \
\begin{tabular}{c} Bandgap at 300 K \\ Bandgap Narrowing Energy \\ A\({}_{\text{A},\text{m}}/\)A\({}_{\text{A},\text{p}}\) in Auger Recombination \\ B\({}_{\text{A},\text{m}}/\)B\({}_{\text{A},\text{p}}\) in Auger Recombination \\ C\({}_{\text{A},\text{m}}/\)C\({}_{\text{A},\text{p}}\) in Auger Recombination \\ H in Auger Recombination \\ N\({}_{0}\) in Auger Recombination \\ E\({}_{0}\) in Impact Ionization \\ \(\hbar\omega_{\text{op}}\) in Impact Ionization \\ \(\text{a}_{0n}/\)a\({}_{\text{op}}\) in Impact Ionization \\ \(\text{b}_{0n}/\)b\({}_{\text{op}}\) in Impact Ionization \\ \(\text{b}_{0n}/\)b\({}_{\text{op}}\) in Impact Ionization \\ \end{tabular} &
\begin{tabular}{c} 1 \(\times\) 10\({}^{18}\) cm\({}^{-3}/1\times 10^{18}\) cm\({}^{-3}\) \\ \(4\times 10^{15}\) V/cm \\ 1.4 eV \\ 1.4 eV \\ 1.4686 \(\times\) 10\({}^{6}\) cm\({}^{-1}/\)5.5222 \(\times\) 10\({}^{6}\) cm\({}^{-1}\) \\ 1.2075 \(\times\) 10\({}^{7}\) V/cm/1.2724 \(\times\) 10\({}^{7}\) V/cm \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Model parameters for the simulations. Figure 3: (**a**) Output characteristics curves compared with the experimental results [33; 34] at T = 300 K for Vgs = 7 V to Vgs = 10 V. (**b**) Transfer characteristic curve compared with the experimental results [33; 34] at T = 300 K for Vds = 10 V.