Phase change material switch circuit for enhanced signal isolation and methods of forming the same

A device structure comprising:

• a first series connection of a first phase change memory (PCM) switch and a second PCM switch;
• and
• a second series connection of a third PCM switch and a fourth PCM switch, wherein:
• the first PCM switch comprises a first heater line, a first phase change material (PCM) line located in proximity to the first heater line, a first contact electrode located on a first end of the first PCM line, and a second contact electrode located on a second end of the first PCM line;
• the second PCM switch comprises a second heater line, a second PCM line located in proximity to the second heater line, a third contact electrode located on a first end of the second PCM line, and a fourth contact electrode located on a second end of the second PCM line;
• the third PCM switch comprises a third heater line, a third PCM line located in proximity to the third heater line, a fifth contact electrode located on a first end of the third PCM line, and a sixth contact electrode located on a second end of the third PCM line;
• the fourth PCM switch comprises a fourth heater line, a fourth PCM line located in proximity to the fourth heater line, a seventh contact electrode located on a first end of the fourth heater line, and an eighth contact electrode located on a second end of the fourth heater line;
• the first contact electrode is electrically connected to the fifth contact electrode;
• the second contact electrode is electrically connected to the third contact electrode;
• the sixth contact electrode is electrically connected to the seventh contact electrode;
• the fourth contact electrode and the eighth contact electrode are electrically grounded;
• the first PCM line and the second PCM line have a same height;
• the first PCM line has a first width;
• the second PCM line has a second width;
• and
• the first width is greater than the second width.

A circuit, comprising:

• a first series connection of a first phase change memory (PCM) switch and a second PCM switch;
• and
• a programming circuit located on a top surface of a substrate that underlies the first series connection, wherein:
• the first PCM switch comprises a first heater line, a first phase change material (PCM) line located in proximity to the first heater line, a first contact electrode located on a first end of the first PCM line, and a second contact electrode located on a second end of the first PCM line;
• the second PCM switch comprises a second heater line, a second PCM line located in proximity to the second heater line, a third contact electrode located on a first end of the second PCM line, and a fourth contact electrode located on a second end of the second PCM line;
• the second contact electrode is electrically connected to the third contact electrode;
• the fourth contact electrode is electrically grounded;
• one of the first contact electrode and the second contact electrode comprises an radio-frequency (RF) signal input port;
• another of the first contact electrode and the second contact electrode comprises an RF signal output port;
• and
• the programming circuit is configurated to apply a set of complementary programming pluses across the first heater line and the second heater line, the set of complementary programming pulses comprising an amorphization-inducing programming pulse that induces a high resistivity state in one of the first PCM line and the second PCM line and a crystallization-inducing programming pulse that induces a low resistivity state in another of the first PCM line and the second PCM line.