Phase change nano electro-mechanical relay

Patent metadata

Field	Value
Publication number	US-11742162-B2
Application number	US-201917294906-A
Country	US
Kind code	B2
Filing date	Dec 18, 2019
Priority date	Dec 19, 2018
Publication date	Aug 29, 2023
Grant date	Aug 29, 2023

Abstract

A MEMS/NEMS actuator based on a phase change material is described in which the volumetric change observed when the phase change material changes from a crystalline phase to an amorphous phase is used to effectuate motion in the device. The phase change material may be changed from crystalline phase to amorphous phase by heating with a heater or by passing current directly through the phase change material, and thereafter quenched quickly by dissipating heat into a substrate. The phase change material may be changed from the amorphous phase to a crystalline phase by heating at a lower temperature. An application of the actuator is described to fabricate a phase change nano relay in which the volumetric expansion of the actuator is used to push a contact across an airgap to bring it into contact with a source/drain.

First claim

We claim:

1. An actuator comprising:
a substrate;
an isolation layer, covering all or a portion of the substrate;
a first insulating layer, covering all or a portion of the isolation layer;
a phase change material, covering a portion of the first insulating layer; and
a second insulating layer covering the phase change material;
wherein the phase change material is encapsulated between the first and second insulating layers; and
wherein a phase transition between a crystalline phase and an amorphous phase of the phase change material causes a movement of the second insulating layer.

2. The actuator of claim 1 , the phase change material being transitioned from the crystalline phase to the amorphous phase by heating all or a portion of the phase change material at or above a melting point of the phase change material.

3. The actuator of claim 2 , the phase change material being a conductive material, the phase change material changing phase by applying a voltage to the phase change material.

4. The actuator of claim 2 , further comprising:
a heater, disposed between the isolation layer and the first insulating layer, wherein the phase change material is heated by passing a current through the heater.

5. The actuator of claim 4 , the heater comprising tungsten.

6. The actuator of claim 1 , the phase change material being a chalcogenide glass, a perovskite nickelate or a rare earth perovskite.

7. The actuator of claim 6 , the phase change material comprising GeTe.

8. The actuator of claim 2 , the phase change material transitioning from the amorphous phase to the crystalline phase when heated to a second temperature, lower than the melting point.

9. The actuator of claim 8 , the phase change material exhibiting a decrease in volume when changed from the amorphous phase to the crystalline phase.

10. The actuator of claim 1 wherein the first and second insulating layers are composed of Al 2 O 3 and the isolation layer is composed of aluminum nitride.

11. The actuator of claim 2 wherein the phase change material is transitioned to the amorphous phase by applying a 7 V 200 ns pulse to the phase change material.

12. The actuator of claim 2 wherein the phase change material is transitioned to the crystalline phase by applying a 6V 200 ns pulse to the phase change material.

Assignees

• Univ Carnegie Mellon

Inventors

• Best James
• Piazza Gianluca

Classifications

• H01H37/36 Primary

  actuated due to expansion or contraction of a fluid with or without vaporisation (the fluid forming a contact of the switch H01H29/04, H01H29/30) · CPC title

• H01H1/0094 Primary

  Switches making use of nanoelectromechanical systems [NEMS] · CPC title

• H01H2300/036

  Application nanoparticles, e.g. nanotubes, integrated in switch components, e.g. contacts, the switch itself being clearly of a different scale, e.g. greater than nanoscale · CPC title

• H01H37/48

  with extensible rigid rods or tubes · CPC title