Field Effect Transistors (FETs), Integrated Circuit (IC) chips including the FETs, and a method of forming the FETs and IC. FET locations define FET pedestals on a layered semiconductor wafer that may include a III-V semiconductor surface layer, e.g., Gallium Arsenide (GaAs), and a buried layer, e.g., Aluminum Arsenide (AlAs). A dielectric material, e.g., Aluminum Oxide (AlO), surrounds pedestals at least in FET source/drain regions. A conductive cap caps channel sidewalls at opposite channel ends. III-V on insulator (IIIVOI) devices form wherever the dielectric material layer is thicker than half the device length. Source/drain contacts are formed to the caps and terminate in/above the dielectric material in the buried layer.