GRAPHENE CAPPED HEMT DEVICE

A graphene capped HEMT device and a method of fabricating same are disclosed. The graphene capped HEMT device includes one or more graphene caps that enhance device performance and/or reliability of an exemplary AlGaN/GaN heterostructure transistor used in high-frequency, high-energy applications, e.g., wireless telecommunications. The HEMT device disclosed makes use of the extraordinary material properties of graphene. One of the graphene caps acts as a heat sink underneath the transistor, while the other graphene cap stabilizes the source, drain, and gate regions of the transistor to prevent cracking during high-power operation. A process flow is disclosed for replacing a three-layer film stack, previously used to prevent cracking, with a one-atom thick layer of graphene, without otherwise degrading device performance. In addition, the HEMT device disclosed includes a hexagonal boron nitride adhesion layer to facilitate deposition of the compound nitride semiconductors onto the graphene.