Phase-change material (PCM) radio frequency (RF) switches with stressor layers and contact adhesion layers

• US 10,454,027 B1
• Filed: 02/05/2019
• Issued: 10/22/2019
• Est. Priority Date: 08/14/2018
• Status: Active Grant

• Current Assignee: Newport Fab, LLC (Tower Semiconductor Limited)
• Original Assignee: Newport Fab, LLC (Tower Semiconductor Limited)
• Inventors: Howard, David J., Rose, Jefferson E., Slovin, Gregory P., El-Hinnawy, Nabil
• Primary Examiner(s): Bernstein, Allison
• Application Number:
  US16/267,719
• Time in Patent Office: 259 Days
• 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 70/801 Constructional details of multistable switching devices
• 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 70/8825 Selenides, e.g. GeSe
• CPC Class Codes: H10N 70/8828 Tellurides, e.g. GeSbTe

Abstract

A radio frequency (RF) switch includes a stressed phase-change material (PCM) and a heating element underlying an active segment of the stressed PCM and extending outward and transverse to the stressed PCM. In one approach, at least one transition layer is situated over the stressed PCM. An encapsulation layer is situated over the at least one transition layer and on first and second sides of the stressed PCM. A stressor layer is situated over the encapsulation layer and the said stressed PCM. Alternatively or additionally, contacts of the RF switch extend into passive segments of a PCM, wherein adhesion layers adhere the passive segments of the PCM to the contacts.

Claims

1. A radio frequency (RF) switch comprising:

a stressed phase-change material (PCM) and a heating element underlying an active segment of said stressed PCM and extending outward and transverse to said stressed PCM;

passive segments of said stressed PCM situated under contacts of said RF switch;

at least one transition layer situated over said stressed PCM;

an encapsulation layer situated over said at least one transition layer and on first and second sides of said stressed PCM;

a stressor layer situated over said encapsulation layer and said stressed PCM.

2. The RF switch of claim 1, further comprising a contact dielectric situated over said stressor layer.

3. The RF switch of claim 1, wherein said stressor layer comprises material selected from the group consisting of silicon nitride (Si_XN_Y) and silicon oxynitride (Si_XO_YN_Z).

4. The RF switch of claim 1, wherein said stressor layer comprises a carbon ceramic.

5. The RF switch of claim 1, wherein said at least one transition layer comprises a germanium oxide (Ge_XO_Y) transition layer, a silicon oxide (Si_XO_Y), and a silicon nitride (Si_XN_Y) transition layer.

6. The RF switch of claim 1, wherein said at least one transition layer comprises a germanium nitride (Ge_XN_Y) transition layer and a silicon nitride (Si_XN_Y) transition layer.

7. The RF switch of claim 1, wherein said at least one transition layer comprises a germanium oxynitride (Ge_XO_YN_Z) transition layer and a silicon oxynitride (Si_XO_YN_Z) transition layer.

8. The RF switch of claim 1, wherein said stressed PCM is selected from the group consisting of germanium telluride (Ge_XTe_Y), germanium antimony telluride (Ge_XSb_YTe_Z), germanium selenide (Ge_XSe_Y), and any other chalcogenide.

9. A radio frequency (RF) switch comprising:

a phase-change material (PCM) and a heating element underlying an active segment of said PCM and extending outward and transverse to said PCM;

contacts of said RF switch extending into passive segments of said PCM;

adhesion layers adhering said passive segments of said PCM to said contacts.

10. The RF switch of claim 9, wherein said adhesion layers line said contacts.

11. The RF switch of claim 9, wherein said adhesion layers further adhere said passive segments of said PCM to a contact dielectric situated over said PCM.

12. The RF switch of claim 9, wherein said adhesion layers comprise titanium nitride (TiN).

13. A radio frequency (RF) switch comprising:

a stressed phase-change material (PCM) and a heating element underlying an active segment of said stressed PCM and extending outward and transverse to said stressed PCM;

at least one transition layer situated over said stressed PCM;

an encapsulation layer situated over said at least one transition layer and on first and second sides of said stressed PCM;

a stressor layer situated over said encapsulation layer and said stressed PCM;

contacts of said RF switch extending into passive segments of said stressed PCM;

adhesion layers adhering said passive segments of said stressed PCM to said contacts.

14. The RF switch of claim 13, further comprising a contact dielectric situated over said stressor layer.

15. The RF switch of claim 13, wherein said stressor layer comprises material selected from the group consisting of silicon nitride (Si_XN_Y) and silicon oxynitride (Si_XO_YN_Z).

16. The RF switch of claim 13, wherein said stressor layer comprises a carbon ceramic.

17. The RF switch of claim 13, wherein said at least one transition layer comprises a germanium oxide (Ge_XO_Y) transition layer, a silicon oxide (Si_XO_Y), and a silicon nitride (Si_XN_Y) transition layer.

18. The RF switch of claim 13, wherein said adhesion layers line said contacts.

19. The RF switch of claim 13, wherein said adhesion layers further adhere said passive segments of said stressed PCM to said at least one transition layer.

20. The RF switch of claim 13, wherein said adhesion layers comprise titanium nitride (TIN).