In this paper we report the first hybrid Phase-Change — Tunnel FET (PC-TFET) device configurations for achieving a deep sub-thermionic steep subthreshold swing at room temperature and subthreshold power savings. The proposed hybrid device feedbacks the steep transition of Metal-Insulator transition in a VO2 structure into Gate or Source configurations of strained silicon nanowire Tunnel FETs, to achieve a switching with lon/Ioff better that 5.5×106 and with a subthreshold swing of 4.0 mV/dec at 25 °C. We demonstrate that the principle of PC-TFET switching relates to an internal amplification resulting in a sub-unity body factor, m, which is reduced to values below 0.1 for a current range larger than 2–3 decades. We report a full experimenta...