a method of forming a compound semiconductor substrate includes providing a crystalline base substrate having a first semiconductor material and a main surface , and forming a first semiconductor layer on the main surface and having a pair of tracks disposed on either side of active device regions . the first semiconductor layer is formed from a second semiconductor material having a different coefficient of thermal expansion than the first semiconductor material . the pair of tracks have a relatively weaker crystalline structure than the active device regions . the method further includes thermally cycling the base substrate and the first semiconductor layer such that the first semiconductor layer expands and contracts at a different rate than the base substrate . the pair of tracks physically decouple adjacent ones of the active device regions during the thermal cycling .