Channel engineered tunnel FET for reduced ambipolar nature

Ambipolar conduction is a subject of grave concern for the steep subthreshold slope tunnel field-effect transistor (TFET) to use it in CMOS circuits. For this, we present a graded channel TFET (GD TFET) to suppress the ambipolar nature of device for wide span of gate to source voltage. Regarding this, half of the channel portion adjacent to source is considered lightly doped whereas, remaining half of the channel portion near to drain is considered heavily doped which modulates the energy bands at the drain channel interface. This leads to disturbance in the abruptness of bands at drain/channel junction resulting into poor band to band tunneling generation rate, hence reduced ambipolar nature of the device is obtained. The device behaviour is compared with the conventional TFET and optimization of heavily doped channel section length is also presented.