Rapid thermal chemical vapor deposition (RTCVD) is a processing technique that results from the combination of radiant heating lamps and a CVD chamber. It is the ultimate cold-wall CVD reactor and allows one to clean wafers in-situ and immediately thereafter deposit epitaxial layers. Very thin layers (<100 Å) can be deposited by either gas or lamp power switching. We report here the growth of high quality Si and Si-Ge layers, both intrinsic and in-situ doped, and the in-situ growth of a heterojunction bipolar transistor. These HJBT's show gains as high as 350 and are promising as microwave transistors. RTCVD processing is a production-worthy technology that will play an important role in the manufacture of future heterostructural devices.