A thin film transistor includes a post on a substrate. The post has a height dimension extending away from the substrate to a top, and an edge along the height dimension. A cap covers the top of the post and extends to a distance beyond the edge of the post to define a reentrant profile. A conformal conductive gate layer is located on the edge of the post in the reentrant profile and not over the cap, and includes a portion that extends along the substrate. A conformal insulating layer is on the gate layer in the reentrant profile. A conformal semiconductor layer is on the insulating layer in the reentrant profile. First and second electrodes are located in contact with a first portion of the semiconductor layer over the cap and a second portion of the semiconductor layer not over the post, respectively.