The current disclosure describes a tunnel FET device including a P-I-N heterojunction structure. A high-K dielectric layer and a metal gate wrap around the intrinsic channel layer with an interlayer positioned between high-K dielectric layer and the intrinsic channel layer of the P-I-N heterojunction. The interlayer prevents charge carriers from reaching the interface with high-K dielectric layer under the trap-assisted tunneling effect and reduces OFF state leakage.