Mosfet structure with substrate coupled source

摘要

A disclosed MOSFET cell has a source region formed at the top surface of a semiconductor substrate. The top surface source region is electrically coupled to a conductive region at a bottom portion of the substrate by means of a vertical conduit which projects through the substrate from the top surface to the conductive region. A current exchanger is provided extending over the top surface of the substrate and coupling a top surface portion of the vertical conduit to the source region. The current exchanger makes ohmic contact with the source region and with the conduit region and shorts the two regions together such that majority carrier current of the conduit region will be "converted" into majority carrier current of the source region and electrical continuity between the source region and the conductive region of the substrate is established. Respective source regions of multiple MOSFET cells may be interconnected in accordance with this method through a longitudinally extending conductive layer which is typically formed near the bottom surface of semiconductor substrates.