The present disclosure relates to a tunneling field-effect transistor and a fabrication method. One example transistor includes a semiconductor substrate, a semiconductor nanosheet, a source region and a drain region, a dielectric layer, and a gate metal layer. The semiconductor nanosheet is vertically disposed on the semiconductor substrate. The source region and the drain region are connected using a channel. The drain region, the channel, and the source region are disposed on the semiconductor nanosheet in turn. The drain region is in contact with the semiconductor substrate. The source region is located at an end, of the semiconductor nanosheet, far away from the semiconductor substrate. The dielectric layer comprises at least a gate dielectric layer, is disposed on a surface of the semiconductor nanosheet, and surrounds the channel. The gate metal layer is disposed on a surface of the gate dielectric layer and surrounds the gate dielectric layer.