A semiconductor device and method of formation are provided. The semiconductor device includes a channel surrounding a dielectric tube and a gate surrounding the channel. The dielectric tube comprises a high dielectric constant material that has or conducts few to no carriers, such as electrons or holes. The presence of the dielectric tube confines carriers to the channel, which is in close proximity to the gate. The proximity of the channel, and the carriers therein, to the gate affords greater control to the gate over the carriers, thus allowing a length of the channel to be decreased while experiencing little to no short channel effects, such as current leakage through the channel.