Vertical transistor device fabricated with semiconductor regrowth

A vertical transistor device is characterized by active regions vertically separated by a narrower control region. The control region is defined by conducting layer extensions which extend into a groove within which semiconductor material is regrown during device fabrication. The device is further characterized by regions of isolating material, located horizontally adjacent to the active regions, said isolating material serving to reduce parasitic capacitance and improve thermal distribution within the device, thereby improving frequency and power performance.