Method for manufacturing a laterally limited, single-crystal region on a substrate and the employment thereof for the manufacture of an MOS transistor and a bipolar transistor

摘要

A method for the manufacture of a laterally limited single crystal region that is suitable for use as an active part of a transistor, including the steps of: a) providing a substrate made of a single crystal semiconductor material; b) forming a first layer on a surface of the substrate, said first layer being selectively etchable with respect to the substrate; c) forming a second layer on the first layer, the second layer being selectively etchable with respect to the first layer; d) providing an opening in the first and second layers so as to expose an area on the surface of the substrate; e) covering surfaces and sidewalls of the second layer with a third layer f) selectively etching the first layer with respect to the substrate and the second layer and the third layer so as to provide an undercut between the second layer and the surface of the substrate; g) forming a single crystal region on the exposed surface of the substrate by selective epitaxy without nucleation occurring at the surface of the third layer; h) forming a collector in the substrate under the single-crystal region; i) forming a base in the single-crystal region; j) doping and configuring the second layer such that it forms a base terminal; and k) forming an emitter above the base.