A protective passivation structure is provided for a thermal ink jet printing head which employs a resistive heating element formed of phosphorus-diffused silicon. The passivation structure includes a layer of silicon nitride over the heating element with a layer of silicon carbide over the silicon nitride...http://www.google.de/patents/US4513298?utm_source=gb-gplus-sharePatent US4513298 - Thermal ink jet printhead
