An Improved Si Tunnel Field Effect Transistor With a Buried Strained Si₁₋ₓGeₓ Source

We report on experimental and simulated results of tunneling field-effect transistors (TFETs) with a Si channel and a strained Si 1-x Ge x source. The fabricated TFET with a tensile strained Si channel shows comparably large on-currents and a subthreshold slope of 80 mV/dec at 300 K for a drain current range of three orders of magnitude. A novel TFET structure is proposed to enhance the on-currents by using a buried Si 1-x Ge x source. The overlap between the top thin Si channel and the buried SiGe source increases the tunneling area. Simulations indicate that this structure significantly improves the performance.