Capping layer for insulator in micro-fluid ejection heads

摘要

A micro-fluid ejection head has a resistor layer defining a heater element. An insulative layer underlies the heater element and a capping layer on the insulative layer substantially prevents ion mobility between the resistor and insulative layers. Resistance stability of the heater has been shown improved as has adhesion of the heater to the insulator. Representative layers include insulation of methyl silesquioxane (MSQ) in a thickness of about 5000 Angstroms or more, while the cap is a silicon nitride in a thickness of about 2000 Angstroms or less. Other capping layers include silicon carbide, silicon oxide or dielectrics. The resistor layer typifies TaAlN in a thickness of about 350 Angstroms, including overlying anode and cathode conductors that define the heater. Coating layers are also disclosed as are thermal barrier layers.