Monolithic silicon integrated circuit chip for a thermal ink jet printer

Claim 1

A thermal ink jet printing module comprising an ink channel structure with a plurality of nozzles at one end and an ink supply at the other end, said structure fixedly adjoined to an integrated circuit which contains driver logic and resistive ink heating elements formed on the surface of a common silicon wafer, said circuit comprising, a p-type silicon substrate with a patterned field oxide layer grown on said substrate, followed by gate oxide growth to form a gate oxide layer, at least one transistor switch having a source and drain region formed on said substrate surface said drain region comprising a lightly doped n-type drift region and an n + ion implanted region laterally displaced from the drift region, said transistor switch having an n - type polysilicon gate formed upon said gate oxide layer and in close physical proximity to said source and drain regions, and conductive vias contacting said source and drain regions at said n + ion implanted region, said vias providing electrical connection between said transistor switch and said resistive elements whereby said n + ion implanted region in at least the drain region creates a carrier depletion region upon application of input signals to the vias resulting in a reduction in the electric field at the gate-drain p-n junction.