The present disclosure presents a novel structure for a dielectric material for use with Group III-V material systems and a method of fabricating such a structure. More specifically, the present disclosure describes a novel dielectric layer that is formed on the top surface of a III-V material where the dielectric layer comprises a first region in contact with the top surface of the III-V material crystalline and a second region adjacent to the first region and at the upper side of the dielectric layer. The dielectric layer has material properties different from traditional dielectric layers as it is composed of both crystalline and amorphous structures. The crystalline structure is at the interface with the III-V material (such as AlGaN or GaN) but gradually transitions into an amorphous structure, both within the same layer and both comprising the same material.