Embodiments of the present disclosure describe structural configurations of an integrated circuit (IC) device such as a high electron mobility transistor (HEMT) switch device and method of fabrication. The IC device includes a buffer layer formed on a substrate, a channel layer formed on the buffer layer to provide a pathway for current flow in a transistor device, a spacer layer formed on the channel layer, a barrier layer formed on the spacer layer, the barrier layer including aluminum (Al), nitrogen (N), and at least one of indium (In) or gallium (Ga), a gate dielectric directly coupled with the spacer layer or the channel layer, and a gate formed on the gate dielectric, the gate being directly coupled with the gate dielectric. Other embodiments may also be described and/or claimed.