A thermally stabilized cascode heterojunction bipolar transistor (TSC-HB) having the current and power generation regions in separate temperature zones, each transistor collector in a cold zone connected directly and individually to an emitter terminal of a corresponding transistor in a hot zone, thereby limiting the current available to the emitter of the transistor in the hot zone. Such an interconnection of transistors prevents the transistor in the hot zone from drawing more current from other transistor sources when increases in temperature occur. This achieves thermal stability and prevents the transistors from overheating and burning out.