Various embodiments of the present application are directed toward an integrated chip (IC). The IC comprises a dielectric structure disposed over a substrate. A phase change material (PCM) structure is disposed over the dielectric structure. A first conductive structure and a second conductive structure are disposed over and electrically coupled to the PCM structure. A heating structure is disposed in the dielectric structure and laterally between the first conductive structure and the second conductive structure. The heating structure has a first surface and a second surface opposite the first surface. The first surface faces the PCM structure. The first surface has a first width and the second surface has a second width that is greater than the first width.