Among other things, one or more techniques for forming a vertical tunnel field effect transistor (FET), and a resulting vertical tunnel FET are provided herein. In an embodiment, the vertical tunnel FET is formed by forming a core over a first type substrate region, forming a second type channel shell around a circumference greater than a core circumference, forming a gate dielectric around a circumference greater than the core circumference, forming a gate electrode around a circumference greater than the core circumference, and forming a second type region over a portion of the second type channel shell, where the second type has a doping opposite a doping of the first type. In this manner, line tunneling is enabled, thus providing enhanced tunneling efficiency for a vertical tunnel FET.