Continuing with FIG. 4, structure 400 illustrates that, by the deposition of P type silicon-germanium layer 418 (and the addition and formation of junctions and other structures not shown), a lateral silicon-germanium PNP HBT is formed wherein silicon-germanium layer 418, through amorphous silicon layer 416, functions as the P type emitter, well 408 functions as the N type base and implant 426 fun