Tunnel transistor

A method of fabricating a tunnel field-effect transistor device, comprising:

• obtaining a structure including a semiconductor substrate and a plurality of vertically extending mandrels on the semiconductor substrate;
• forming dummy gates on sidewalls of the mandrels;
• removing the mandrels after forming the dummy gates, thereby forming first vertical trenches between pairs of the dummy gates;
• forming first and second epitaxial source regions on the semiconductor substrate, the first and second epitaxial source regions having a first conductivity type;
• forming first and second source contacts within the first vertical trenches, the source contacts being electrically connected to the first and second epitaxial source regions and comprising a first electrically conductive material;
• forming first and second source contact caps comprising a first dielectric material on the first and second source contacts;
• forming an epitaxial drain region on the semiconductor substrate, the drain region having a second conductivity type opposite from the first conductivity type;
• forming a drain contact on the epitaxial drain region, the drain contact comprising a second electrically conductive material different from the first electrically conductive material;
• forming a drain contact cap comprising a second dielectric material different from the first dielectric material on the drain contact;
• removing the dummy gates;
• depositing a gate dielectric layer over a channel region of the semiconductor substrate;
• forming a first gate electrode on the gate dielectric layer;
• and
• forming a first gate cap over the first gate electrode, the first gate cap comprising a third dielectric material different from the first and second dielectric materials, the method, further including:
• depositing an interlevel dielectric layer over the first and second source contact caps, the drain cap, and the first gate cap;
• forming a first wiring trench in the interlevel dielectric layer exposing top surfaces of the first and second source contact caps, the drain contact cap and the first gate cap;
• removing portions of the first and second source contact caps selectively to the drain contact cap and the first gate cap using a first selective etch;
• and
• depositing source wiring metal within the first wiring trench and on top surfaces of the first and second source contacts, thereby forming an electrically conductive source wiring strap electrically connecting the first and second source contacts.