Phase change material (PCM) switch having low heater resistance

An integrated chip (IC), comprising:

• a dielectric structure disposed over a semiconductor substrate;
• a phase change material (PCM) structure disposed over the dielectric structure, wherein the PCM structure is configured to change between a first resistive state and a second resistive state, and wherein a relative permittivity of the dielectric structure is less than a relative permittivity of the PCM structure;
• a first conductive structure disposed over and electrically coupled to the PCM structure;
• a second conductive structure disposed over and electrically coupled to the PCM structure, wherein the first conductive structure and the second conductive structure are laterally spaced apart along a plane;
• a heating structure disposed in the dielectric structure and laterally between the first conductive structure and the second conductive structure, wherein:
• the PCM structure overlies the heating structure;
• the heating structure has a first portion and a second portion;
• the first portion is disposed vertically between the second portion and the PCM structure;
• the first portion has a first width along the plane;
• the second portion has a second width along the plane;
• the second width is greater than the first width;
• and
• an insulator structure disposed vertically between the heating structure and the PCM structure, wherein the insulator structure has a third width that is substantially the same as the first width.

An integrated chip (IC), comprising:

• a silicon substrate;
• a dielectric structure disposed over the silicon substrate;
• a phase change material (PCM) structure disposed over the dielectric structure, wherein a relative permittivity of the dielectric structure is less than a relative permittivity of the PCM structure;
• a first conductive structure disposed over the PCM structure;
• a second conductive structure disposed over the PCM structure, wherein the first conductive structure and the second conductive structure are laterally spaced apart along a plane and have nearest neighboring sidewalls spaced apart by a first opening having a first width;
• a heating structure having a first portion disposed in the dielectric structure and a second portion disposed in the dielectric structure below the first portion;
• an insulator structure disposed vertically between the heating structure and the PCM structure;
• wherein:
• the first portion of the heating structure has outer sidewalls which are spaced below the first opening and which are spaced apart by a second width that is less than the first width;
• the second portion of the heating structure has outer sidewalls which are spaced below the first opening and which are spaced apart by a third width that is greater than the first width;
• and
• the insulator structure has outer sidewalls that terminate at the outer sidewalls of the first portion.