Patent ID: 6102528
Filing Date: 2000-08-15
Classification: B41J

Abstract:
A drive transistor for switching heating elements of a thermal ink jet printhead which is formed on a p-type silicon substrate contained in a printhead comprising:an elongated drain region being connected to a respective heating element;source regions spaced from the drain region, the source regions being connected to ground;an elongated, oval-shaped gate region having elongated, parallel portions;channel regions formed under the elongated, parallel portions of the gate region, which are adjacent to the source and drain region and located therebetween, the gate region being connected to a printhead addressing means from which electrical signals are selectively applied to the gate region, thereby activating the transistor and enabling the application of a current pulse to a selected heating element for the ejection of an ink droplet from the printhead;the drain region having a lightly doped n.sup.- type drift region offset from an n.sup.+ ion implanted contact region;each source region being comprised of an n.sup.+ ion implanted region; anda p-type pocket implant underneath the entire channel region of each gate region and at least extending from the channel region into the substrate to an adjacent source region and into the drift region for about 1 .mu.m, whereby a shorter source region to drain region spacing is provided without loss of breakdown voltage, and a suitable drive transistor may be provided for high resolution printheads.