Uniform Plate Slot Contacts for Improving Performance in Phase-Change Material (PCM) Radio Frequency (RF) Switches

• US 20200136041A1
• Filed: 12/27/2019
• Published: 04/30/2020
• 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, DeBer, Michael J.
• Granted Patent: US 10,707,414 B2
• Time in Patent Office: 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 70/253 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 70/841 Electrodes
• 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 phase-change material (PCM) and a heating element underlying an active segment of the PCM, the PCM and heating element being situated over a substrate. A contact dielectric is over the PCM. PCM contacts have upper portions and uniform plate slot lower portions. The uniform plate slot lower portions have a total plate resistance R_PLATE, and a total plate slot interface resistance R_PLATE-INT. The upper portions have a total capacitance C_UPPER to the uniform plate slot lower portions, and the PCM has a total capacitance C_PCM to the substrate. The uniform plate slot lower portions significantly reduce a product of (R_PLATE+R_PLATE-INT) and (C_UPPER+C_PCM). As an alternative to the uniform plate slot lower portions, PCM contacts have segmented lower portions. The segmented lower portions significantly reduce C_UPPER.

Claims

1-22. -22. (canceled)

23. :

A radio frequency (RF) switch comprising;

a phase-change material (PCM) and a heating element approximately underlying an active segment of said PCM, said PCM and heating element being situated over a substrate;

a contact dielectric over said PCM;

PCM contacts comprising upper portions and uniform plate slot lower portions;

said uniform plate slot lower portions having a total plate resistance R_PLATE, and a total plate slot interface resistance R_PLATE-INT;

said upper portions having a total capacitance C_UPPER to said uniform plate slot lower portions, said PCM having a total capacitance C_PCM to said substrate;

said uniform plate slot lower portions resulting in significantly reducing a product of (R_PLATE+R_PLATE-INT) and (C_uppper+C_PCM), wherein said uniform plate slot lower portions are narrow plates so as to reduce said total capacitance C_PCM to said substrate.

24. :

The RF switch of claim 23, further comprising a thermally conductive and electrically insulating layer under said PCM.

25. :

The RF switch of claim 24, wherein said thermally conductive and electrically insulating layer comprises a material selected from the group consisting of aluminum nitride (AlN), aluminum oxide (Al_XO_Y), beryllium oxide (Be_XO_Y), silicon carbide (SiC), diamond, and diamond-like carbon.

26. :

The RF switch of claim 24, wherein a thickness of said contact dielectric is significantly greater than a thickness of said thermally conductive and electrically insulating layer.

27. :

The RF switch of claim 23, wherein said PCM comprises a material 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.

28. :

The RF switch of claim 23, wherein a contact uniformity support layer is situated over said PCM, wherein said contact uniformity support layer comprises nitride.

29. :

The RF switch of claim 23, wherein a contact uniformity support layer is situated over said PCM, wherein said contact uniformity support layer comprises a bi-layer that includes oxide and nitride.

30. :

The RF switch of claim 23, wherein a contact uniformity support layer is situated over said PCM, wherein said contact uniformity support layer significantly reduces said total plate slot interface resistance R_PLATE-INT.

31. :

The RF switch of claim 23, wherein said contact dielectric comprises a material selected from the group consisting of SiO₂, boron-doped SiO₂, phosphorous-doped SiO₂, Si_XN_Y, fluorinated silicon dioxide, carbon-doped silicon oxide, and spin-on organic polymer.

32. :

The RF switch of claim 23, wherein said uniform plate slot lower portions and said upper portions of said PCM contacts comprise a material selected from the group consisting of tungsten, aluminum, and copper.

33. :

The RF switch of claim 23, wherein said uniform plate slot lower portions are narrow plates so as to reduce an area of said PCM such that said total capacitance C_PCM to said substrate is reduced.

34. :

The RF switch of claim 23, wherein said uniform plate slot lower portions are narrow plates so as to connect to a top portion of said PCM without connecting to a sidewall of said PCM.

35. :

A radio frequency (RF) switch comprising;

a phase-change material (PCM) and a heating element, said PCM and heating element being situated over a substrate, said PCM having a total capacitance C_PCM to said substrate;

PCM contacts comprising upper portions and uniform plate slot lower portions;

said uniform plate slot lower portions being narrow plates so as to reduce said total capacitance C_PCM to said substrate.

36. :

The RF switch of claim 35, wherein a contact uniformity support layer is situated over said PCM, wherein said contact uniformity support layer significantly reduces a total plate slot interface resistance R_PLATE-INT.

37. :

The RF switch of claim 36, wherein said contact uniformity support layer comprises nitride.

38. :

The RF switch of claim 36, wherein said contact uniformity support layer comprises a bi-layer that includes oxide and nitride.

39. :

The RF switch of claim 35, further comprising a thermally conductive and electrically insulating layer under said PCM.

40. :

The RF switch of claim 39, wherein said thermally conductive and electrically insulating layer comprises a material selected from the group consisting of aluminum nitride (AlN), aluminum oxide (Al_XO_Y), beryllium oxide (Be_XO_Y), silicon carbide (SiC), diamond, and diamond-like carbon.

41. :

The RF switch of claim 35, wherein said PCM comprises a material 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.

42. :

The RF switch of claim 35, wherein said uniform plate slot lower portions and said upper portions of said PCM contacts comprise a material selected from the group consisting of tungsten, aluminum, and copper.