Environmentally robust passivation structures for high-voltage silicon carbide semiconductor devices

An improved termination structure for high field semiconductor devices in silicon carbide comprising:

• a silicon carbide-based device for high-field operation;
• an active region in said device;
• an edge termination passivation for said active region, in which said edge termination passivation includes,
• an oxidation layer on the silicon carbide portions adjacent said active region for lowering the interface density between said silicon carbide portions and said oxidation layer;
• a first sputtered non-stoichiometric silicon nitride layer on said oxidation layer for reducing parasitic capacitance and minimizing device trapping;
• a second sputtered non-stoichiometric silicon nitride layer on said first layer for positioning subsequent passivation layers further from said substrate without encapsulating said structure;
• a sputtered stoichiometric silicon nitride layer on said second sputtered layer for encapsulating said structure and for enhancing the hydrogen barrier properties of the passivation layers;
• and
• a chemical vapor deposited environmental barrier layer of stoichiometric silicon nitride for step coverage and crack prevention on said encapsulant layer.