Method of manufacturing phase-change material (PCM) radio frequency (RF) switch using a chemically protective and thermally conductive layer

A radio frequency (RF) switch includes a heating element, an aluminum nitride layer situated over the heating element, and a phase-change material (PCM) situated over the aluminum nitride layer. An inside segment of the heating element underlies an active segment of the PCM, and an intermediate segment of the heating element is situated between a terminal segment of the heating element and the inside segment of the heating element. The aluminum nitride layer situated over the inside segment of the heating element provides thermal conductivity and electrical insulation between the heating element and the active segment of the PCM. The aluminum, nitride layer extends into the intermediate segment of the heating element and provides chemical protection to the intermediate segment of the heating element, such that the intermediate segment of the heating element remains substantially unetched and with substantially same thickness as the inside segment.