Silicon carbide (SiC) has a number of unique properties such as a wide band gap, higher breakdown electric field than in silicon, good thermal conductivity, high saturation velocity, and a reasonable bulk mobility. Additionally, SiC can grow a native oxide, thereby enabling its use in metal-oxide-semiconductor devices. All these properties make it an excellent candidate for high power electronics.

Nevertheless, wide commercialization of SiC is hindered by its surface/channel mobility which is substantially lower than that of the bulk material. This mobility reduction is attributed to a high concentration of defects at the SiC/SiO₂ interface. These defects are also responsible for a bunch of detrimental phenomena such as the hysteresis seen in current-voltage (I-V) characteristics, bias temperature instability (BTI), and hot-carrier-degradation (HCD). Therefore, comprehensive modeling of pristine SiC transistors and reliability phenomena in these devices should be based on a consistent set of microscopic defect physics. As such, the primary goal of this project is to develop and validate a physics-based modeling framework which considers self-consistently all these parasitic effects as a response of interface and oxide defects/precursors which can be charged/activated by different driving forces.

We expect that oxide traps are responsible for the temperature behavior and the hysteresis of I-V characteristics as well as for BTI. Therefore, these two phenomena will be tackled consistently. Nevertheless, a possible contribution of pre-existing interface traps will also be checked. The interface traps will be modeled using Shockley-Read-Hall theory, while oxide traps will be described within the nonradiative multiphonon four states model. The strategy to distinguish between these traps relies on different behavior of their capture/emission times. As for HCD, in SiC transistors it has two main contributions, i.e. interface trap generation and charging/discharging of oxide traps. The interplay of these mechanisms will be carefully analyzed. We also plan to extract defect properties. This extraction will be performed during optimization of the model parameters and using the characterization technique based on the analysis of capture/emission times of the defects. The defect properties obtained using these two methods will be compared against each other and with results of ab initio calculations.

This defect-centric framework will ensure a comprehensive description of degradation mechanisms in SiC devices, thereby making it suitable for predictive reliability simulations. Furthermore, the information on the defect properties will be of great importance for applied physics, material science, and electrical engineering. The obtained results will be disseminated to the scientific community and the model will be made available through the software release channels of the host institute.