Increasing the thickness and quality of 3C-SiC grown on Si wafers to enable 1200V devices

Anvil’s unique patented 3C-SiC/Si material and devices will shrink power converters in size, weight and cost, whilst significantly increasing efficiency. Conventional SiC devices (4H-SiC) enable many of these improvements but the cost is too prohibitive for many applications. Anvil is currently developing 650V 3C-SiC MOSFETs and diodes using the 3C-SiC material already developed, but 1200V devices require thicker SiC layers (12µm instead of 8µm) and as wafer bow levels scale with growth thickness, it requires additional stress relief techniques to enable fabrication of the 1200V devices required for many applications within the $billion market for PV inverters, electric vehicles, UPS’s and industrial motors. The stress relief is achieved by carefully tuning the growth parameters and starting substrate. This multi-variable growth process has been optimised using experimentation and numerical modelling and has resulted in low bow, high crystal quality wafers for 650V devices. Extending this to 1200V is not just a case of extending the final growth phase but needs a re-optimisation of the whole growth process with significant experimentation with variables, extrapolation of the models, and characterisation of the grown material using electron microscope and X-ray diffraction.