An Improved Si Tunnel Field Effect Transistor With a Buried Strained Si 1−x Ge x Source

We report on experimental and simulated results of tunneling field-effect transistors (TFETs) with a Si channel and as trained Si 1−xGex 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 Si1−xGex 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. Index Terms—SiGe, strained Si (sSi), subthreshold swing (SS), tunneling field-effect transistors (TFETs).