A heterojunction bipolar transistor (HBT), and manufacturing method therefor, comprising a semiconductor substrate having a collector region, a number of insulating layers over the semiconductor substrate, at least one of the number of insulating layers having a base cavity over the collector region, a base structure of a compound semiconductive material in the base cavity, a window in the insulating layer over the base cavity, an emitter structure in the window, an interlevel dielectric layer, and connections through the interlevel dielectric layer to the base structure, the emitter structure, and the collector region. The base structure and the emitter structure preferably are formed in the same processing chamber.