# US 10,770,389 B2 · Phase-change material (PCM) radio frequency (RF) switches with capacitively coupled RF terminals > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,770,389 B2 - Document ID: US10770389B2 - Status: Granted - Kind: B2 - Application number: 16/231,121 - Filed: 2018-12-21 - Published: 2020-02-20 - Granted: 2020-09-08 - Earliest claimed: 2018-08-14 - Assignees: Newport Fab, LLC - Applicants: Newport Fab, LLC - Inventors: Nabil El-Hinnawy; Gregory P. Slovin; Jefferson E. Rose; David J. Howard - Web page: https://patentgrep.com/patent/US10770389B2 ## CPC - H10W 20/495: {Capacitive arrangements or effects of, or between wiring layers} - H10W 20/496: {Capacitor integral with wiring layers} - H10B 63/10: Phase change RAM [PCRAM, PRAM] devices - H10N 70/231: {based on solid-state phase change, e.g. between amorphous and crystalline phases, Ovshinsky effect} - H10N 70/823: {adapted for essentially horizontal current flow, e.g. bridge type devices} - H10N 70/8413: {adapted for resistive heating} - H10N 70/8613: {Heating or cooling means other than resistive heating electrodes, e.g. heater in parallel} - H10N 70/8825: {Selenides, e.g. GeSe} - H10N 70/8828: {Tellurides, e.g. GeSbTe} - H10N 79/00: Integrated devices, or assemblies of multiple devices, comprising at least one solid-state element covered by group H10N70/00 (ReRAM devices H10B63/00; PCRAM devices H10B63/10) - H10W 44/20: at high-frequency [HF] or radio frequency [RF] - H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10 - H10B: ELECTRONIC MEMORY DEVICES - H10N: ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR ## Abstract A radio frequency (RF) switch includes a phase-change material (PCM), a heating element underlying an active segment of the PCM and extending outward and transverse to the PCM, and RF terminals having lower metal portions and upper metal portions. At least one of the lower metal portions can be ohmically separated from and capacitively coupled to passive segments of the PCM, while the upper metal portions are ohmically connected to the lower metal portions. Alternatively, the lower metal portions can be ohmically connected to passive segments of the PCM, while a capacitor is formed in part by at least one of the upper metal portions. Alternatively, at least one of the RF terminals can have a trench metal liner separated from a trench metal plug by a dielectric liner. The trench metal liner can be ohmically connected to passive segments of the PCM, while the trench metal plug is ohmically separated from, but capacitively coupled to, the trench metal liner. ## Claims ### Claim 1 A radio frequency (RF) switch comprising: a phase-change material (PCM) and a heating element approximately underlying an active segment of said PCM and extending outward and transverse to said PCM; RF terminals comprising lower metal portions and upper metal portions; at least one of said lower metal portions of said RF terminals being ohmically separated from and capacitively coupled to passive segments of said PCM; said upper metal portions of said RF terminals being ohmically connected to said lower metal portions of said RF terminals. ### Claim 2 (depends on 1) The RF switch of claim 1, wherein said lower metal portions of said RF terminals are capacitively coupled to said passive segments of said PCM by a capacitor formed by said passive segments of said PCM, an RF terminal dielectric segment, and said lower metal portions of said RF terminals. ### Claim 3 (depends on 2) The RF switch of claim 2, wherein said RF terminal dielectric segment comprises material selected from the group consisting of SiO2, boron-doped SiO2, phosphorous-doped SiO2, and SiXNY. ### Claim 4 (depends on 1) The RF switch of claim 1, wherein said PCM is selected from the group consisting of germanium telluride (GeXTeY), germanium antimony telluride (GeXSbYTeZ), germanium selenide (GeXSeY), and any other chalcogenide. ### Claim 5 (depends on 1) The RF switch of claim 1, further comprising a thermally conductive and electrically insulating layer situated over said heating element. ### Claim 6 (depends on 5) The RF switch of claim 5, wherein said thermally conductive and electrically insulating layer comprises material selected from the group consisting of aluminum nitride (AlN), aluminum oxide (AlXOY), beryllium oxide (BeXOY), silicon carbide (SiC), diamond, and diamond-like carbon. ### Claim 7 (depends on 1) The RF switch of claim 1, wherein said lower metal portions comprise material selected from the group consisting of tungsten (W), aluminum (Al), and copper (Cu). ### Claim 8 (depends on 1) The RF switch of claim 1, wherein said upper metal portions comprise a multi-layer stack of an interconnect metal. ### Claim 9 (depends on 8) The RF switch of claim 8, wherein said upper metal portions comprise material selected from the group consisting of aluminum (Al) and copper (Cu). ### Claim 10 A radio frequency (RF) switch comprising: a phase-change material (PCM) and a heating element approximately underlying an active segment of said PCM and extending outward and transverse to said PCM; a lower metal portion of an RF terminal being capacitively coupled to a passive segment of said PCM; an upper metal portion of said RF terminal being ohmically connected to said lower metal portion of said RF terminal. ### Claim 11 (depends on 10) The RF switch of claim 10, wherein said lower metal portion of said RF terminal is capacitively coupled to said passive segment of said PCM by a capacitor formed by said passive segment of said PCM, an RF terminal dielectric segment, and said lower metal portion of said RF terminal. ### Claim 12 (depends on 11) The RF switch of claim 11, wherein said RF terminal dielectric segment comprises material selected from the group consisting of SiO2, boron-doped SiO2, phosphorous-doped SiO2, and SiXNY. ### Claim 13 (depends on 10) The RF switch of claim 10, wherein said lower metal portion comprises material selected from the group consisting of tungsten (W), aluminum (Al), and copper (Cu). ### Claim 14 (depends on 10) The RF switch of claim 10, wherein said upper metal portion comprises a multi-layer stack of an interconnect metal. ### Claim 15 (depends on 14) The RF switch of claim 14, wherein said upper metal portion comprises material selected from the group consisting of aluminum (Al) and copper (Cu). ### Claim 16 (depends on 10) The RF switch of claim 10, wherein said PCM is selected from the group consisting of germanium telluride (GeXTeY), germanium antimony telluride (GeXSbYTeZ), germanium selenide (GeXSeY), and any other chalcogenide. ### Claim 17 (depends on 10) The RF switch of claim 10, further comprising a thermally conductive and electrically insulating layer situated over said heating element. ### Claim 18 (depends on 17) The RF switch of claim 17, wherein said thermally conductive and electrically insulating layer comprises material selected from the group consisting of aluminum nitride (AlN), aluminum oxide (AlXOY), beryllium oxide (BeXOY), silicon carbide (SiC), diamond, and diamond-like carbon. ### Claim 19 A method for fabricating a radio frequency (RF) switch, said method comprising: forming a phase-change material (PCM) and a heating element approximately underlying an active segment of said PCM and extending outward and transverse to said PCM; forming a lower metal portion of an RF terminal capacitively coupled to a passive segment of said PCM; forming an upper metal portion of said RF terminal ohmically connected to said lower metal portion of said RF terminal. ### Claim 20 (depends on 19) The method of claim 19, wherein said lower metal portion of said RF terminal is capacitively coupled to said passive segment of said PCM by a capacitor formed by said passive segment of said PCM, an RF terminal dielectric segment, and said lower metal portion of said RF terminal.