Vertical channel field effect transistor (vcfet) with reduced contact resistance and/or parasitic capacitance, and related fabrication methods

Abstract

Vertical channel field-effect transistors (VCFETs) with reduced contact resistance and/or parasitic capacitance, and related fabrication methods. In exemplary aspects, to reduce contact resistance of the VCFET, an end portion of the vertical channel has a semiconductor structure that has an expanded width in the horizontal direction parallel to the substrate surface. This provides a greater area to form a contact for a source/drain to reduce contact resistance of the VCFET. To reduce the parasitic capacitance between the gate and a contact of the VCFET, the spacer includes one or more air gaps that form an air spacer(s) between the gate and the contact to reduce the overall average permittivity of the spacer. In one example, the air spacer(s) of the VCFET is elongated in the horizontal direction parallel to the substrate surface (and perpendicular to the vertical direction of the vertical channel) to further reduce the parasitic capacitance.