Planar semiconductor integrated circuits including improved bipolar transistor structures and method of fabricating such circuits.

摘要

In a planar semiconductor integrated circuit, a buried isolating layer (9) confines equal area PN junctions of a vertical bipolar transistor (3) and a lateral bipolar transistor (5) to the intrinsic regions of the transistors. This avoids the formation of parasitic PN junctions and so leads to improved performance when the transistors are operated in saturation as in TTL circuits. A method of making such an integrated circuit involves the simultaneous deposition of polycrystalline semiconductor on the isolating layer and monocrystalline semiconductor onto the substrate through holes in the isolating layer. Alternatively, a thin nucleating film may be first deposited on the isolating layer so that monocrystalline semiconductor can be deposited on the isolating layer as well as on the substrate.