Various embodiments of the present disclosure are directed toward an integrated chip including an undoped layer overlying a substrate. A first barrier layer overlies the undoped layer. A doped layer overlies the first barrier layer. Further, a second barrier layer overlies the first barrier layer, where the second barrier layer is laterally offset from a perimeter of the doped layer by a non-zero distance. The first and second barrier layers comprise a same III-V semiconductor material. A first atomic percentage of a first element within the first barrier layer is less than a second atomic percentage of the first element within the second barrier layer.