Patent ID: 8664715
Filing Date: 2014-03-04
Classification: H01L

Abstract:
1. An isolated transistor formed in a semiconductor substrate of a first conductivity type, the isolated transistor comprising: a well of the first conductivity type at a surface of the substrate; a source region of a second conductivity type opposite to the first conductivity type at the surface of the substrate within the well; a drain region of the second conductivity type spaced apart from the source region at the surface of the substrate; a gate located above the surface of the substrate between the source region and the drain region; a subsurface shielding region of the first conductivity type disposed in the substrate and having a doping concentration greater than a doping concentration of the substrate, the subsurface shielding region being distinct from the well and submerged in the substrate beneath the well; and a drain clamping region of the first conductivity type submerged in an isolated pocket of the substrate beneath the drain region and having a doping concentration greater than the doping concentration of the substrate, the drain clamping region being laterally separated from the subsurface shielding region.