Embodiments herein describe techniques, systems, and method for a semiconductor device. Embodiments herein may present a semiconductor device including a substrate with a surface that is substantially flat. A channel area including an III-V compound may be above the substrate, where the channel area is an epitaxial layer directly in contact with the surface of the substrate. A gate dielectric layer is adjacent to the channel area and in direct contact with the channel area, while a gate electrode is adjacent to the gate dielectric layer. Other embodiments may be described and/or claimed.