Multichannel devices with gate structures to increase breakdown voltage

A transistor device is provided that includes a base structure and a superlattice structure that overlies the base structure. The superlattice structure comprises a multichannel ridge having sides that extend to the base structure. The multichannel ridge comprises a plurality of heterostructures that each form a channel of the multichannel ridge. A three-sided gate configuration is provided that wraps around and substantially surrounds the top and sides of the multichannel ridge along at least a portion of its depth. The three-sided gate configuration is configured to re-distribute peak electric fields along the three-sided gate configuration to facilitate the increase in breakdown voltage of the transistor device.