An uncompensated silicon bipolar junction transistor fabricated using molecular beam epitaxy

The first silicon bipolar junction transistor fabricated using molecular beam epitaxy is reported. Epitaxial layers defining the collector, base, and emitter regions are grown successively at 850°C. Because no thermal diffusion steps are involved, junction location and base width are precisely defined. The final structure is mesa isolated using reactive ion etching. A peak forward current gain of 60 is measured. This technique is expected to be applicable to the development of very narrow base, ultrahigh speed bipolar transistors.