# US 10,873,024 B2 · Providing thermal shield to RRAM cells > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,873,024 B2 - Document ID: US10873024B2 - Status: Granted - Kind: B2 - Application number: 16/392,500 - Filed: 2019-04-23 - Published: 2020-10-29 - Granted: 2020-12-22 - Earliest claimed: 2019-04-23 - Applicants: Tetramem Inc. - Inventors: Minxian Zhang; Ning Ge - Web page: https://patentgrep.com/patent/US10873024B2 ## CPC - H10N 70/8616: {Thermal insulation means} - H10N 70/063: {by etching of pre-deposited switching material layers, e.g. lithography} - 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} - H10N 70/011: {Manufacture or treatment of multistable switching devices} - H10N 70/24: {based on migration or redistribution of ionic species, e.g. anions, vacancies} - H10N 70/826: {adapted for essentially vertical current flow, e.g. sandwich or pillar type devices} - H10N 70/8833: {Binary metal oxides, e.g. TaOx} - H10N: ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR - H10B: ELECTRONIC MEMORY DEVICES ## Abstract The technology of a crossbar array circuit and method of improving thermal shielding are disclosed. An example apparatus includes a bottom wire; a first vertical thermal shielding layer formed on the bottom wire, a bottom electrode formed on the first vertical thermal shielding layer; a filament forming layer formed on the bottom electrode; a top electrode formed on the filament forming layer; a second vertical thermal shielding layer formed on the top electrode; a top wire formed on the second vertical thermal shielding layer, wherein the filament forming layer is configured to form a filament within the filament forming layer when applying a switching voltage upon the filament forming layer, and wherein a material of the first vertical thermal shielding layer and the second vertical thermal shielding layer includes ReOx, RuOx, IrOx, ITO, a combination thereof, or an alloy or doping thereof (with or without other thermally conductive materials). ## Claims ### Claim 1 An apparatus comprising: a bottom wire; a first vertical thermal shielding layer formed on the bottom wire; a bottom electrode formed on the first vertical thermal shielding layer; a filament forming layer formed on the first vertical thermal shielding layer; a top electrode formed on the filament forming layer; a second vertical thermal shielding layer formed on the top electrode; a top wire formed on the second vertical thermal shielding layer, wherein the filament forming layer is configured to form a filament within the filament forming layer when applying a switching voltage upon the filament forming layer, and wherein a material of the first vertical thermal shielding layer and the second vertical thermal shielding layer comprises ReOx, RuOx, IrOx, ITO, a combination thereof, or an alloy or doping thereof. ### Claim 2 (depends on 1) The apparatus as claimed in claim 1, wherein a thermal conductivity of the first vertical thermal shielding layer or the second vertical thermal shielding layer is lower or higher than that of the lateral thermal shielding layer. ### Claim 3 (depends on 1) The apparatus as claimed in claim 1, wherein a thermal conductivity of the first vertical thermal shielding layer or the second vertical thermal shielding layer is lower than 50 W/m-k. ### Claim 4 (depends on 1) The apparatus as claimed in claim 1, wherein an electrical conductivity of the first vertical thermal shielding layer or the second vertical thermal shielding layer is higher than that of the lateral thermal shielding layer. ### Claim 5 (depends on 1) The apparatus as claimed in claim 1, wherein an electrical conductivity of the first vertical thermal shielding layer or the second vertical thermal shielding layer is lower than that of the top electrode and the bottom electrode. ### Claim 6 (depends on 1) The apparatus as claimed in claim 1, wherein an electrical conductivity of the first vertical thermal shielding layer or the second vertical thermal shielding layer is higher than 106 S/m (Siemens per meter). ### Claim 7 (depends on 1) The apparatus as claimed in claim 1, wherein a material of the bottom electrode or the top electrode comprises Pt, Ti, TiN, Pd, Ir, W, Ta, Hf, Nb, V, TaN, NbN, or any combination or alloy of other electrically conductive materials thereof. ### Claim 8 (depends on 1) The apparatus as claimed in claim 1, wherein a material of the filament forming layer comprises TaOx (where x≤2.5), HfOx (where x≤2.0), TiOx (where x≤2.0), ZrOx (where x≤2.0) or a combination thereof. ### Claim 9 (depends on 1) The apparatus as claimed in claim 1, wherein the filament forming layer is configured to form a filament within the filament forming layer when a set voltage/current is applied on the filament forming layer. ### Claim 10 (depends on 9) The apparatus as claimed in claim 9, wherein a material of the filament comprises Ta-rich, Hf-rich, Ti-rich, or Zr-rich oxide material. ### Claim 11 (depends on 1) The apparatus as claimed in claim 1, further comprises a lateral thermal shielding layer isolating the filament forming layer, the bottom electrode, and the top electrode from the bottom wire and the top wire. ### Claim 12 (depends on 11) The apparatus as claimed in claim 11, wherein the lateral thermal shielding layer is formed on the substrate and encapsulates a sidewall of the filament forming layer, the first vertical thermal shielding layer, the second vertical thermal shielding layer, the bottom electrode, and the top electrode. ### Claim 13 (depends on 11) The apparatus as claimed in claim 11, wherein a material of the lateral thermal shielding layer comprises Al2O3, SiO2, SiN, MgO, TiO2, AlOxNy, SiOxNy or a combination thereof. ### Claim 14 A method comprising: forming a bottom wire on a substrate; forming a first vertical thermal shielding layer on the bottom wire; forming a bottom electrode on the first vertical thermal shielding layer; forming a filament forming layer on the bottom electrode; forming a top electrode on the filament forming layer; forming a second vertical thermal shielding layer on the top electrode; and forming a top wire on the second thermal shielding layer, wherein a material of the first vertical thermal shielding layer and the second vertical thermal shielding layer comprises ReOx, RuOx, IrOx, ITO, a combination thereof, or an alloy or doping thereof. ### Claim 15 (depends on 14) The method as claimed in claim 14, further comprising: forming a lateral thermal shielding layer covering a sidewall of the filament forming layer, the first vertical thermal shielding layer, the second vertical thermal shielding layer, the bottom electrode, and the top electrode.