In fabricating a radio frequency (RF) switch, a heat spreader is provided and a heating element is deposited. A thermally conductive and electrically insulating material is deposited over the heating element. The heating element and the thermally conductive and electrically insulating material are patterned, where the thermally conductive and electrically insulating material is self-aligned with the heating element. A layer of an upper dielectric is deposited. A conformability support layer is optionally deposited over the upper dielectric and the thermally conductive and electrically insulating material. A phase-change material is deposited over the optional conformability support layer and the underlying upper dielectric and the thermally conductive and electrically insulating material.