Method to make phase-change material RF switches with thermal dielectrics

• US 9,368,720 B1
• Filed: 10/30/2014
• Issued: 06/14/2016
• Est. Priority Date: 05/06/2014
• Status: Active Grant

• Current Assignee: HRL Laboratories LLC (The Boeing Co.)
• Original Assignee: HRL Laboratories LLC (The Boeing Co.)
• Inventors: Seo, Hwa-Chang, Moon, Jeong-Sun
• Primary Examiner(s): Prenty, Mark
• Application Number:
  US14/528,945
• Time in Patent Office: 593 Days
• US Class Current: 1/1
• CPC Class Codes: H10N 70/011 Manufacture or treatment of multistable switching devices
• CPC Class Codes: H10N 70/231 based on solid-state phase change, e.g. between amorphous and crystalline phases, Ovshinsky effect
• CPC Class Codes: H10N 70/823 adapted for essentially horizontal current flow, e.g. bridge type devices
• CPC Class Codes: H10N 70/8613 Heating or cooling means other than resistive heating electrodes, e.g. heater in parallel
• CPC Class Codes: H10N 70/8828 Tellurides, e.g. GeSbTe

Abstract

A switch includes an input port, an output port, a phase change material coupled between the input port and the output port, a heater, and a thermal dielectric layer in between the heater and the phase change material, and in contact with the heater and the phase change material. The thermal dielectric layer provides thermal conduction between the phase change material and the heater, and the thermal dielectric layer is nonmetallic and electrically non-conductive and includes polycrystalline AlN, diamond, or SiC.

Claims

1. A switch comprising:

an input port;

an output port;

a phase change material coupled between the input port and the output port;

a heater; and

a thermal dielectric layer in between the heater and the phase change material, and in contact with the heater and the phase change material;

wherein the thermal dielectric layer provides thermal conduction between the phase change material and the heater; and

wherein the thermal dielectric layer is nonmetallic and electrically non-conductive and comprises polycrystalline AlN, or diamond.

2. The switch of claim 1 wherein the phase change material comprises a binary compound of Ge_xTe_1-x.

3. The switch of claim 1 further comprising:

a substrate; and

wherein the heater is in direct contact with the substrate.

4. The switch of claim 3 wherein the substrate comprises Si, high resistance Si, sapphire, borofloat, quartz, fused silica, SiGe, or III-V compounds including GaN, InAs, InSb, and InP.

5. The switch of claim 1 further comprising:

a substrate; and

a SiO₂ dielectric layer on the substrate;

wherein the heater is in direct contact with the SiO₂ dielectric layer.

6. The switch of claim 1 further comprising:

an encapsulating layer over the phase change material on a side of the phase change material opposite the thermal dielectric layer.

7. The switch of claim 6 wherein the encapsulating layer comprises SiO₂ or AlN.

8. The switch of claim 1:

wherein the thermal dielectric layer is a thermal via; and

wherein the thermal via has an extent that is less than an extent of the phase change material.

9. The switch of claim 1 wherein:

the switch has an insertion loss less than 0.5 dB and an isolation of greater than 25 dB over a frequency range from 0 to 50 GHz.

10. The switch of claim 1 wherein:

the switch has a switching speed up to 10 THz.

11. A method of fabricating a switch, the method comprising:

providing a heater coupled to a substrate;

forming a thermal dielectric layer on the heater;

forming phase change material on the thermal dielectric layer;

forming an input port in contact with the phase change material; and

forming an output port in contact with the phase change material, wherein the output port is not in contact with the input port;

wherein the thermal dielectric layer provides thermal conduction between the phase change material and the heater; and

wherein the thermal dielectric layer is nonmetallic and electrically non-conductive and comprises polycrystalline AlN, or diamond.

12. The method of claim 11 wherein the phase change material comprises a binary compound of Ge_xTe_1-x.

13. The method of claim 11 wherein the substrate comprises Si, high resistance Si, sapphire, borofloat, quartz, fused silica, SiGe, or III-V compounds including GaN, InAs, InSb, and InP.

14. The method of claim 11 further comprising:

forming a SiO₂ dielectric layer on the substrate;

wherein the SiO₂ dielectric layer is between the heater and the substrate.

15. The method of claim 11 further comprising:

forming an encapsulating layer over the phase change material on a side of the phase change material opposite the thermal dielectric layer.

16. The method of claim 15 wherein the encapsulating layer comprises SiO₂ or AlN.

17. The method of claim 11:

wherein the thermal dielectric layer is a thermal via; and

wherein the thermal via has an extent that is less than an extent of the phase change material.

18. The method of claim 11:

wherein the switch has an insertion loss less than 0.5 dB and an isolation of greater than 25 dB over a frequency range from 0 to 50 GHz.

19. The method of claim 11:

wherein the switch has a switching speed up to 10 THz.

20. The method of claim 11:

wherein the heater is in direct contact with the substrate.