Reduced leakage transistors with germanium-rich channel regions

摘要

Techniques are disclosed for fabricating semiconductor transistor devices configured with a sub-fin insulation layer that reduces parasitic leakage (i.e., current leakage through a portion of an underlying substrate between a source region and a drain region associated with a transistor). The parasitic leakage is reduced by fabricating transistors with a sacrificial layer in a sub-fin region of the substrate below at least a channel region of the fin. During processing, the sacrificial layer in the sub-fin region is removed and replaced, either in whole or in part, with a dielectric material. The dielectric material increases the electrical resistivity of the substrate between corresponding source and drain portions of the fin, thus reducing parasitic leakage.