A photonic semiconductor device and method are provided that ensure that the surface of the device upon completion of the SAG process is planar, or at least substantially planar, such that performance of the subsequent processes is facilitated, thereby enabling higher manufacturing yield to be achieved. A photonic semiconductor device and method are also provided that ensure that the isolation region of the device will have high resistance and low capacitance, without requiring the placement of a thick dielectric material beneath each of the contact pads. Eliminating the need to place thick dielectric materials underneath the contact pads eliminates the risk that the contact pads will peel away from the assembly.