A packaged semiconductor device, in particular a gallium nitride semiconductor structure including a lower semiconductor layer and an upper semiconductor layer disposed over a portion of the lower semiconductor layer. The semiconductor structure includes a plurality of mesas projecting upwardly from the lower layer, each of the mesas including a portion of the upper layer and defining an upper contact surface separated form adjacent mesas by a portion of the lower layer surface. The device further includes a die mounting support, wherein the bottom surface of the die is attached to the top surface of the die mounting support; and a plurality of spaced external conductors extending from the support, at least once of said spaced external conductors having a bond wire post at one end thereof; with a bonding wire extending between the bond wire post and a contact region to the top surface of the plurality of mesas.