Integrated phase change switch

• US 9,362,492 B2
• Filed: 08/25/2014
• Issued: 06/07/2016
• Est. Priority Date: 08/25/2014
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm Switch Corp. (Qualcomm, Inc.)
• Inventors: Goktepeli, Sinan, Stuber, Michael A.
• Primary Examiner(s): CLARK, JASMINE JHIHAN B
• Application Number:
  US14/468,074
• Publication Number:
  US 20160056373A1
• Time in Patent Office: 652 Days
• US Class Current: 1/1
• CPC Class Codes: H10B 63/22 of the metal-insulator-metal type
• CPC Class Codes: H10B 63/30 comprising selection components having three or more electrodes, e.g. transistors
• CPC Class Codes: H10B 63/80 Arrangements comprising multiple bistable or multi-stable switching components of the same type on a plane parallel to the substrate, e.g. cross-point arrays
• CPC Class Codes: H10N 70/021 Formation of the switching material, e.g. layer deposition
• CPC Class Codes: H10N 70/063 by etching of pre-deposited switching material layers, e.g. lithography
• 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 70/235 between different crystalline phases, e.g. cubic and hexagonal
• CPC Class Codes: H10N 70/253 having three or more terminals, e.g. transistor-like devices
• CPC Class Codes: H10N 70/823 adapted for essentially horizontal current flow, e.g. bridge type devices
• CPC Class Codes: H10N 70/8413 adapted for resistive heating
• CPC Class Codes: H10N 70/8613 Heating or cooling means other than resistive heating electrodes, e.g. heater in parallel
• CPC Class Codes: H10N 70/882 Compounds of sulfur, selenium or tellurium, e.g. chalcogenides
• CPC Class Codes: H10N 70/8828 Tellurides, e.g. GeSbTe

Abstract

Various methods and devices that involve phase change material (PCM) switches are disclosed. An exemplary integrated circuit comprises an active layer with a plurality of field effect transistor (FET) channels for a plurality of FETs. The integrated circuit also comprises an interconnect layer comprising a plurality of conductive interconnects. The plurality of conductive interconnects couple the plurality of field effect transistors. The integrated circuit also comprises an insulator layer covering at least a portion of the interconnect layer. The integrated circuit also comprises a channel of a radio-frequency (RF) PCM switch. The channel of the RF PCM switch is formed on the insulator layer.

Claims

1. An integrated circuit comprising:

an active layer comprising a plurality of field effect transistor channels for a plurality of field effect transistors;

an interconnect layer comprising a plurality of conductive interconnects, wherein the plurality of conductive interconnects couple the plurality of field effect transistors;

an insulator layer covering at least a portion of the interconnect layer; and

a channel of a radio-frequency phase change material switch, wherein the channel of the radio-frequency phase change material switch is formed on the insulator layer.

2. The integrated circuit of claim 1, wherein the radio-frequency phase change material switch comprises:

a phase change material channel;

a heating element; and

a thermally conductive dielectric located between the phase change material channel and the heating element.

3. The integrated circuit of claim 2, wherein:

the phase change material channel comprises a chalcogenide alloy;

the heating element comprises a metal selected from a group consisting of copper and aluminum; and

the thermally conductive dielectric comprises a dielectric selected from a second group consisting of silicon dioxide and silicon nitride.

4. The integrated circuit of claim 2, further comprising:

a second channel of a second radio-frequency phase change material switch, wherein the second channel of the second radio-frequency phase change material switch is formed over the insulator layer;

a control circuit that controls when the heating element heats the phase change material channel; and

a single pole double throw switch comprising the first and second radiofrequency phase change material switches;

wherein the first and second radio-frequency phase change material switches are both coupled to an antenna contact.

5. The integrated circuit of claim 2, wherein:

the insulator layer and the thermally conductive dielectric comprise a single layer of deposited material; and

the heating element is a top layer of metal in the interconnect layer.

6. The integrated circuit of claim 5, wherein:

the heating element is a strip of the top layer of metal in the interconnect layer;

the top layer of metal in the interconnect layer is a metal-insulator-metal capacitor metal; and

the insulator layer is a metal-insulator-metal capacitor dielectric.

7. The integrated circuit of claim 2, wherein the radio-frequency phase change material switch further comprises:

a second heating element that overlaps a portion of the phase change material channel; and

a second thermally conductive dielectric located between the phase change material and the second heating element;

wherein the phase change material channel is located between the first and second thermally conductive dielectrics and is centered with the first and second heating elements; and

wherein the phase change material channel is coupled to a via that contacts the phase change material channel at a location that lies outside of the first portion of the phase change material channel.

8. The integrated circuit of claim 7, further comprising:

a top-level dielectric layer surrounding the via; and

a second via with a top portion that is surrounded by the top-level dielectric layer;

wherein a bottom portion of the second via is physically connected to a wire in the interconnect layer; and

wherein the plurality of field effect transistors are complementary metaloxide-semiconductor field effect transistors.

9. The integrated circuit of claim 8, further comprising:

a second channel of a second radio-frequency phase change material switch, wherein the second channel of the second radio-frequency phase change material switch is formed over the insulator layer;

a control circuit that controls when the heating element heats the phase change material channel;

a single pole double throw switch comprising a first throw, a second throw, and the first and second radio-frequency phase change material switches; and

a signal bus configured to accept an external electrical connection;

wherein the first and second radio-frequency phase change material switches are both coupled to the signal bus;

wherein the first radio-frequency phase change material switch is coupled to the first throw;

wherein the second radio-frequency phase change material switch is coupled to the second throw; and

wherein the control circuit comprises the plurality of field effect transistors.

10. The integrated circuit of claim 9, further comprising:

a capacitor that supplies a set pulse to the heating element in response to a signal from the control circuit;

wherein the set pulse is delivered to the heating element in under 10 nanoseconds; and

wherein the first throw and the signal bus are at least three times as wide as the phase change material channel.

11. A monolithic integrated circuit comprising:

a semiconductor substrate that has been doped to form a plurality of active regions for a plurality of field effect transistors;

a radio-frequency phase change material switch having a phase change material channel, a first contact, and a second contact; and

an interconnect layer located between the phase change material channel and the semiconductor substrate, wherein the radiofrequency phase change material switch further comprises;

a heating element; and

a thermally conductive dielectric located between the phase change material channel and the heating element.

12. The monolithic integrated circuit of claim 11, wherein:

the phase change material channel comprises a chalcogenide alloy;

the heating element comprises a metal selected from a group consisting of copper and aluminum; and

the thermally conductive dielectric comprises a dielectric selected from a second group consisting of silicon dioxide and silicon nitride.

13. The monolithic integrated circuit of claim 11, further comprising:

a second channel of a second radio-frequency phase change material switch, wherein the second channel of the second radio-frequency phase change material switch is formed over the insulator layer;

a control circuit that controls when the heating element heats the phase change material channel; and

a single pole double throw switch comprising the first and second radiofrequency phase change material switches;

wherein the first and second radio-frequency phase change material switches are both coupled to an antenna contact.

14. The monolithic integrated circuit of claim 11, wherein:

the insulator layer and the thermally conductive dielectric comprise a single layer of deposited material; and

the heating element is a top layer of metal in the interconnect layer.

15. The monolithic integrated circuit of claim 14, wherein:

the heating element is a strip of the top layer of metal in the interconnect layer;

the top layer of metal in the interconnect layer is a metal-insulator-metal capacitor metal; and

the insulator layer is a metal-insulator-metal capacitor dielectric.

16. The monolithic integrated circuit of claim 11, wherein the radiofrequency phase change material switch further comprises:

a second heating element that overlaps a portion of the phase change material channel; and

a second thermally conductive dielectric located between the phase change material and the second heating element;

wherein the phase change material channel is located between the first and second thermally conductive dielectrics and is centered with the first and second heating elements; and

wherein the phase change material channel is coupled to a first via that contacts the first contact and a second via that contacts the second contact.

17. The monolithic integrated circuit of claim 16, further comprising:

a top-level dielectric layer surrounding the first via and the second via; and

a third via with a top portion that is surrounded by the top-level dielectric layer;

wherein a bottom portion of the third via is physically connected to a wire in the interconnect layer; and

wherein the plurality of field effect transistors are complementary metaloxide-semiconductor field effect transistors.

18. The monolithic integrated circuit of claim 17, further comprising:

a second channel of a second radio-frequency phase change material switch, wherein the second channel of the second radio-frequency phase change material switch is formed over the insulator layer;

a control circuit that controls when the heating element heats the phase change material channel;

a single pole double throw switch comprising a first throw, a second throw, and the first and second radio-frequency phase change material switches; and

a signal bus configured to accept an external electrical connection;

wherein the first and second radio-frequency phase change material switches are both coupled to the signal bus;

wherein the first radio-frequency phase change material switch is coupled to the first throw;

wherein the second radio-frequency phase change material switch is coupled to the second throw; and

wherein the control circuit comprises the plurality of field effect transistors.

19. The monolithic integrated circuit of claim 18, further comprising:

a capacitor that supplies a set pulse to the heating element in response to a signal from the control circuit;

wherein the set pulse is delivered to the heating element in under 10 nanoseconds; and

wherein the first throw and the signal bus are at least three times as wide as the phase change material channel.