Investigation of the Electron Trapping in Commercial Thick Silicon Dioxides Thermally Grown on 4H-SiC under the Constant Current Stress

Since the constant voltage stress Time-Dependent Dielectric Breakdown (CVS-TDDB) based on the thermochemical E model is a conventional method for predicting the lifetime of thermally grown gate oxides in SiC power DMOSFETs, the gate oxide failure mechanism is considered to be field-driven breakdown. P. Moens, et al. questioned through the observation that CVS-TDDB cannot capture the impact of both electron and hole trapping mechanisms on the failure distribution function, thus proposing charge-driven breakdown. This work adopts an electron trapping model under CCS for thermal silicon dioxide (SiO
2
) on Si to validate its applicability to thick thermal SiO
2
on 4H-SiC under stress conditions where the charge trapping mechanism is always dominated by electron trapping without the effect of hole trapping. It is significant in establishing a charge-to-breakdown
$(\boldsymbol{Q}_{BD})$
model for thermally grown gate oxides in commercial SiC devices and in predicting the lifetime under typical operation dominated by electron trapping through
$\boldsymbol{Q}_{BD}$
.