An asymmetric gate tunneling transistor includes a substrate, a first-polarity portion, a second-polarity portion, a channel portion, a gate structure and an insulation body. The first-polarity portion and the second-polarity portion are disposed on the substrate. The channel portion is connected with the first-polarity portion and the second-polarity portion, and includes a first section and a second section. The gate structure includes an enveloping portion surrounding the first section, and a flat portion covering one side of the second section away from the substrate. The insulation body includes a first insulation portion disposed between the first section and the enveloping portion, and a second insulation portion disposed between the second section and the flat portion. Through the asymmetric design of the gate structure, the tunneling transistor is offered with features of a high ON current and a low OFF current. |