A tunnel field transistor (TFET) device includes a fin structure that protrudes from a substrate surface. The fin structure includes a base portion proximate to the substrate surface, a top portion, and a first pair of sidewalls extending from the base portion to the top portion. The first pair of sidewalls has a length corresponding to a length of the fin structure. The fin structure also includes a first doped region having a first dopant concentration at the base portion of the fin structure. The fin structure also includes a second doped region having a second dopant concentration at the top portion of the fin structure. The TFET device further includes a gate including a first conductive structure neighboring a first sidewall of the first pair of sidewalls. A dielectric layer electrically isolates the first conductive structure from the first sidewall.