Patent ID: 9647070
Date: 2017-05-09
CPC Classifications: H01L

Claim:
1. A semiconductor device, comprising: a substrate of a first doping type at a first doping level having first and second surfaces; an active region disposed adjacent the first surface of the substrate with a second doping type opposite in conductivity to the first doping type; circuitry formed in a portion of the active region disposed away from the first surface of the substrate and having at least one region of higher conductivity of the second doping type relative to the doping level in the remainder of the active region proximate the at least one region; at least a portion of the active region proximate the first surface of the substrate and not containing the at least one region defined with a graded dopant concentration, to aid carrier movement from an emitter in the active region to a collector in the substrate, the graded dopant concentration greater proximate the first surface of the substrate.