The present disclosure provides one embodiment of a method of forming a tunnel field effect transistor (TFET). The method includes forming a semiconductor mesa on a semiconductor substrate; performing a first implantation to the semiconductor substrate and the semiconductor mesa to form a drain of a first type conductivity; forming a first dielectric layer on the semiconductor substrate and sidewall of the semiconductor mesa; forming a gate stack on the sidewall of the semiconductor mesa and the first dielectric layer; forming a second dielectric layer on the first dielectric layer and the gate stack; and forming, on the semiconductor mesa, a source having a second type conductivity opposite to the first type conductivity. The gate stack includes a gate dielectric and a gate electrode on the gate dielectric. The source, drain and gate stack are configured to form the TFET.