A method for forming a high electron mobility transistor (HEMT) device with a plurality of alternating layers of one or more undoped gallium nitride (GaN) layers and one or more carbon doped gallium nitride layers (c-GaN), and an HEMT device formed by the method is disclosed. In one embodiment, the method includes forming a channel layer stack on a substrate, the channel layer stack having a plurality of alternating layers of one or more undoped gallium nitride (GaN) layers and one or more carbon doped gallium nitride layers (c-GaN). The method further includes forming a barrier layer on the channel layer stack. In one embodiment, the channel layer stack is formed by growing each of the one or more undoped gallium nitride (GaN) layers in growth conditions that suppress the incorporation of carbon in gallium nitride, and growing each of the one or more carbon doped gallium nitride (c-GaN) layers in growth conditions that promote the incorporation of carbon in gallium nitride.