A new high-voltage planar transistor technology

A new technology for producing P-N planar junctions which show a breakdown voltage very close to that of a plane junction has been developed and applied to the fabrication of a small signal bipolar transistor with VCEO(sus) =1200 volts and a TV horizontal deflection device for line operated TV sets. The "corner" breakdown of the planar junction is eliminated by using a field plate--EQR structure and the breakdown usually occurring at the edge of the field plate is eliminated by using a layer of undoped polysilicon between the two electrodes which gives a linear voltage distribution at the surface.