An improved termination structure for high field semiconductor devices in silicon carbide is disclosed. The termination structure includes a silicon carbide-based device for high-field operation, an active region in the device, an edge termination passivation for the active region, in which the edge termination passivation includes, an oxide layer on at least some of the silicon carbide portions of the device for satisfying surface states and lowering interface density, a non-stoichiometric layer of silicon nitride on the oxide layer for avoiding the incorporation of hydrogen and for reducing parasitic capacitance and minimizing trapping, and, a stoichiometric layer of silicon nitride on the nonstoichiometric layer for encapsulating the nonstoichiometric layer and the oxide layer.