A 4H-SiC Trench MOS Capacitor Structure for Sidewall Oxide Characteristics Measurement

Test structure for evaluating gate oxide properties on the trench sidewall in 4H-SiC is proposed. Using the thick bottom oxide and poly-Silicon spacer structure, we are able to measure the capacitance characteristics directly and extract the interface state density. It is observed that typical NO annealing process cannot passivate the trench etching induced defects effectively.