# US 8,569,728 B2 · Nonvolatile memory with variable resistance change layers > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,569,728 B2 - Document ID: US8569728B2 - Status: Granted - Kind: B2 - Application number: 12/728,579 - Filed: 2010-03-22 - Published: 2010-12-16 - Granted: 2013-10-29 - Earliest claimed: 2009-06-10 - Assignees: Kabushiki Kaisha Toshiba - Applicants: Kensuke Takano; Yoshio Ozawa; Katsuyuki Sekine; Junichi Wada - Inventors: Kensuke Takano; Yoshio Ozawa; Katsuyuki Sekine; Junichi Wada - Web page: https://patentgrep.com/patent/US8569728B2 ## CPC - H10N 70/24: {based on migration or redistribution of ionic species, e.g. anions, vacancies} - G11C 11/5685: {using storage elements comprising metal oxide memory material, e.g. perovskites} - H10B 63/30: {comprising selection components having three or more electrodes, e.g. transistors} - 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} - H10B 63/84: {arranged in a direction perpendicular to the substrate, e.g. 3D cell arrays} - H10N 70/021: {Formation of switching materials, e.g. deposition of layers} - H10N 70/061: {Shaping switching materials} - H10N 70/801: {Constructional details of multistable switching devices} - H10N 70/826: {adapted for essentially vertical current flow, e.g. sandwich or pillar type devices} - H10N 70/841: {Electrodes} - H10N 70/883: {Oxides or nitrides} - H10N 70/8833: {Binary metal oxides, e.g. TaOx} - G11C 13/0007: {comprising metal oxide memory material, e.g. perovskites} - G11C 2213/15: Current-voltage curve - G11C 2213/32: Material having simple binary metal oxide structure - G11C 2213/34: Material includes an oxide or a nitride - G11C 2213/71: Three dimensional array - H10N: ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR - G11C: STATIC STORES (semiconductor memory devices H10B) - H10B: ELECTRONIC MEMORY DEVICES ## Abstract A nonvolatile memory device includes: a first conductive layer; a second conductive layer; a first resistance change layer provided between the first conductive layer and the second conductive layer and having an electrical resistance changing with at least one of an applied electric field and a passed current; and a first lateral layer provided on a lateral surface of the first resistance change layer and having an oxygen concentration higher than an oxygen concentration in the first resistance change layer. ## Claims ### Claim 1 A nonvolatile memory device comprising: a first conductive layer; a second conductive layer; a first resistance change layer provided between the first conductive layer and the second conductive layer and having an electrical resistance configured to change with at least one of an applied electric field or a passed current, the first resistance change layer having a lateral surface intersecting a plane perpendicular to a stacking direction from the first conductive layer toward the second conductive layer; and a first lateral layer contacting the lateral surface of the first resistance change layer, a direction from the first lateral layer toward the lateral surface of the first resistance change layer being perpendicular to the stacking direction, and the first lateral layer having an oxygen concentration higher than an oxygen concentration in the first resistance change layer, wherein the first resistance change layer includes AαMβOγ, and the first lateral layer includes Aα1Mβ1γ1 (γ1>γ), the A being a transition metal element, the M being a transition metal element, the O being oxygen. ### Claim 2 (depends on 1) The device according to claim 1, further comprising: a third conductive layer opposed to a lateral surface of the first conductive layer, the lateral surface of the first conductive layer intersecting a plane perpendicular to the stacking direction; a fourth conductive layer opposed to a lateral surface of the second conductive layer, a direction from third conductive layer toward the fourth conductive layer being parallel to the stacking direction, and the lateral surface of the second conductive layer intersecting a plane perpendicular to the stacking direction; a second resistance change layer provided between the third conductive layer and the fourth conductive layer and having an electrical resistance configured to change with at least one of an applied electric field and a passed current, the second resistance change layer having a lateral surface intersecting a plane perpendicular to the stacking direction; a second lateral layer contacting the lateral surface of the second resistance change layer on a side of the first lateral layer, a direction from the second lateral layer toward the lateral surface of the second resistance change layer being perpendicular to the stacking direction, and the second lateral layer including at least one of a compound having a higher oxygen concentration than the second resistance change layer and an oxide of an element having a smaller absolute value of standard free energy of oxide formation than an element except oxygen contained in an oxide included in the second resistance change layer; and an interlayer insulating film provided between the first lateral layer and the second lateral layer and including an oxide of an element having a smaller absolute value of standard free energy of oxide formation than the element contained in the oxide included in the first lateral layer and the second lateral layer. ### Claim 3 (depends on 1) The device according to claim 1, wherein at least part of the first lateral layer is provided between the first conductive layer and the second conductive layer. ### Claim 4 (depends on 1) The device according to claim 1, wherein the first lateral layer includes a metal oxide having a substantially stoichiometric composition ratio, and the first resistance change layer includes the metal oxide with a proportion of oxygen reduced to 90% or less as compared with the first lateral layer. ### Claim 5 (depends on 1) The device according to claim 1, wherein the first resistance change layer and the first lateral layer include an oxide of at least one selected from the group consisting of Si, Ti, Ta, Nb, Hf, Zr, W, Al, Ni, Co, Mn, Fe, Cu, and Mo. ### Claim 6 (depends on 1) The device according to claim 1, wherein the first conductive layer and the second conductive layer include a material containing an element having a smaller absolute value of standard free energy of oxide formation than an element except oxygen contained in an oxide included in the first resistance change layer. ### Claim 7 (depends on 1) The device according to claim 1, wherein the first conductive layer and the second conductive layer include at least one of W, Ta, Cu, TiN, TaN, WC, and highly doped silicon. ### Claim 8 (depends on 1) The device according to claim 1, wherein a width of the first resistance change layer along a first direction is smaller than a width of the lateral layer along the first direction, the first direction being perpendicular to the stacking direction. ### Claim 9 (depends on 1) The device according to claim 1, wherein a work function of the first conductive layer is different from a work function of the second conductive layer. ### Claim 10 A nonvolatile memory device comprising: a first conductive layer; a second conductive layer; a first resistance change layer provided between the first conductive layer and the second conductive layer and having an electrical resistance configured to change with at least one of an applied electric field and a passed current, the first resistance change layer having a lateral surface intersecting a plane perpendicular to a stacking direction from the first conductive layer toward the second conductive layer; and a first lateral layer contacting the lateral surface of the first resistance change layer, a direction from the first lateral layer toward the lateral surface of the first resistance change layer being perpendicular to the stacking direction, and the first lateral layer including an oxide of an element having a smaller absolute value of standard free energy of oxide formation than an element except oxygen contained in an oxide included in the first resistance change layer, wherein the first resistance change layer includes AαMβOγ, and the first lateral layer includes Aα1Mβ1Oγ1 (γ1>γ), the A being a transition metal element, the M being a transition metal element, the O being oxygen. ### Claim 11 (depends on 10) The device according to claim 10, further comprising: a third conductive layer opposed to a lateral surface of the first conductive layer, the lateral surface of the first conductive layer intersecting a plane perpendicular to the stacking direction; a fourth conductive layer opposed to a lateral surface of the second conductive layer, a direction from the third conductive layer toward the fourth conductive layer being parallel to the stacking direction, and the lateral surface of the second conductive layer intersecting a plane perpendicular to the stacking direction; a second resistance change layer provided between the third conductive layer and the fourth conductive layer and having an electrical resistance configured to change with at least one of an applied electric field and a passed current, the second resistance change layer having a lateral surface intersecting a plane perpendicular to the stacking direction; a second lateral layer contacting the lateral surface of the second resistance change layer on a side of the first lateral layer, a direction from the second lateral layer toward the lateral surface of the second resistance change layer being perpendicular to the stacking direction, and the second lateral layer including at least one of a compound having a higher oxygen concentration than the second resistance change layer and an oxide of an element having a smaller absolute value of standard free energy of oxide formation than an element except oxygen contained in an oxide included in the second resistance change layer; and an interlayer insulating film provided between the first lateral layer and the second lateral layer and including an oxide of an element having a smaller absolute value of standard free energy of oxide formation than the element contained in the oxide included in the first lateral layer and the second lateral layer. ### Claim 12 (depends on 10) The device according to claim 10, wherein at least part of the first lateral layer is provided between the first conductive layer and the second conductive layer. ### Claim 13 (depends on 10) The device according to claim 10, wherein the first resistance change layer and the first lateral layer include an oxide of at least one selected from the group consisting of Si, Ti, Ta, Nb, Hf, Zr, W, Al, Ni, Co, Mn, Fe, Cu, and Mo. ### Claim 14 (depends on 10) The device according to claim 10, wherein the first conductive layer and the second conductive layer include at least one of W, Ta, Cu, TiN, TaN, WC, and highly doped silicon. ### Claim 15 (depends on 10) The device according to claim 10, wherein a width of the first resistance change layer along a first direction is smaller than a width of the lateral layer along the first direction, the first direction being perpendicular to the stacking direction. ### Claim 16 (depends on 10) The device according to claim 10, wherein a work function of the first conductive layer is different from a work function of the second conductive layer.