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) selectively etching the first layer with respect to the substrate and the second layer so as to provide an undercut between the second layer and the surface of the substrate; f) forming a single crystal region on the exposed surface of the substrate by selective epitaxy: g) doping the second layer such that parts of the second layer adjoining the single-crystal region acting as a channel region form a source region and a drain region; h) producing a gate dielectric at a surface of the single-crystal region; and i) forming a gate electrode that is insulated from the source and drain regions on the gate dielectric.