A phase-change material (PCM) switching device is provided. The PCM switching device includes: a base dielectric layer over a semiconductor substrate; a heater element embedded in the base dielectric layer, the heater element comprising a first metal element and configured to generate heat in response to a current flowing therethrough; a self-aligned dielectric layer disposed on the heater element, wherein the self-aligned dielectric layer comprises one of an oxide of the first metal element and a nitride of the first metal element, and the self-aligned dielectric layer is horizontally aligned with the heater element; a PCM region disposed on the self-aligned dielectric layer, wherein the PCM region comprises a PCM operable to switch between an amorphous state and a crystalline state in response to the heat generated by the heater element; and two metal pads electrically connected to the PCM region.