Patent ID: 7265018

Claim:
A method of fabricating a heterobipolar transistor comprising: forming a pedestal atop a structure that comprising at least a base layer located on a surface of a substrate having a collector and trench isolation regions located therein; forming an extra base layer over said structure including said pedestal, wherein said extra base layer comprises monocrystalline material over the substrate and polycrystalline material over the pedestal and said base layer that is located atop said trench isolation regions, said polycrystalline material over said pedestal is thinner than the polycrystalline material over said base layer that is located atop said trench isolation regions; converting at least said polycrystalline material over said pedestal of said extra base layer into an oxide utilizing a low temperature process that is performed at a temperature of about 700° C. or less; removing said oxide and said pedestal from said structure to provide an emitter opening; and forming at least a polysilicon emitter in said emitter opening.