Forming bipolar transistor through fast EPI-growth on polysilicon

摘要

Provided is a semiconductor device that includes a first transistor and a second transistor that are formed on the same substrate. The first transistor includes a first collector, a first base, and a first emitter. The first collector includes a first doped well disposed in the substrate. The first base includes a first doped layer disposed above the substrate and over the first doped well. The first emitter includes a doped element disposed over a portion of the first doped layer. The second transistor includes a second collector, a second base, and a second emitter. The second collector includes a doped portion of the substrate. The second base includes a second doped well disposed in the substrate and over the doped portion of the substrate. The second emitter includes a second doped layer disposed above the substrate and over the second doped well.