Patent ID: 6806513
Filing Date: 2004-10-19
Classification: H01L

Abstract:
A heterojunction bipolar transistor (HBT) comprisinga) an emitter region of one conductivity type, b) a base region of opposite conductivity type abutting the emitter region, material in the emitter region having an energy bandgap that is wider than the energy bandgap of material in the base region. c) a collector region of the one conductivity type abutting the base region, material in the collector region being the same as the material in the base region d) a subcollector region of the one conductivity type and of higher doping concentration than the collector region, and e) an insertion layer of the one conductivity type between and abutting the collector region and the subcollector region and having a lower doping concentration than the subcollector region, material of the insertion layer having an energy bandgap that is wider than the energy bandgap of material in the collector region and the insertion layer is thinner than the collector region.