Application of silane-only selective epitaxy to the fabrication of fully self-aligned silicon bipolar transistors

A fully self-aligned Si bipolar process is described, which uses silane-only epitaxy to selectively grow the collector and base. Electrical measurements on the completed transistors yield a current gain of 189 and ideality factors of 1.004 and 1.15 for the collector and base characteristics respectively. Base leakage currents are observed on some devices, which are traced to oxide etching during epitaxy around the perimeter of the active area.