# US 10,312,440 B2 · Variable resistance element and memory device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,312,440 B2 - Document ID: US10312440B2 - Status: Granted - Kind: B2 - Application number: 15/704,112 - Filed: 2017-09-14 - Published: 2018-09-20 - Granted: 2019-06-04 - Earliest claimed: 2017-03-14 - Assignees: Toshiba Mitsubishi Corporation - Applicants: Toshiba Memory Corporation - Inventors: Hiromichi Kuriyama; Masumi Saitoh; Takayuki Ishikawa; Harumi Watanabe - Web page: https://patentgrep.com/patent/US10312440B2 ## CPC - H10N 70/883: {Oxides or nitrides} - G11C 11/5614: {using conductive bridging RAM [CBRAM] or programming metallization cells [PMC]} - G11C 13/0011: {comprising conductive bridging RAM [CBRAM] or programming metallization cells [PMCs]} - G11C 13/0069: {Writing or programming circuits or methods} - 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 70/023: {by chemical vapor deposition, e.g. MOCVD, ALD} - H10N 70/245: {the species being metal cations, e.g. programmable metallization cells} - H10N 70/826: {adapted for essentially vertical current flow, e.g. sandwich or pillar type devices} - H10N 70/882: {Compounds of sulfur, selenium or tellurium, e.g. chalcogenides} - H10N 70/8833: {Binary metal oxides, e.g. TaOx} - G11C 2213/15: Current-voltage curve - G11C 2213/54: Structure including a tunneling barrier layer, the memory effect implying the modification of tunnel barrier conductivity - H10N: ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR - G11C: STATIC STORES (semiconductor memory devices H10B) - H10B: ELECTRONIC MEMORY DEVICES ## Abstract According to one embodiment, a variable resistance element includes first and conductive layers and first and second layers. The first conductive layer includes a first element including at least one selected from the group consisting of silver, copper, aluminum, nickel, and titanium. The second conductive layer includes at least one selected from the group consisting of platinum, gold, iridium, tungsten, palladium, rhodium, titanium nitride, and silicon. A first layer contacts the first conductive layer, and is provided between the first and second conductive layers. The first layer includes a first material. The first material is insulative. The second layer includes a second element and a second material and is provided between the first layer and the second conductive layer. The second element includes at least one selected from the group consisting of silver, copper, aluminum, nickel, and titanium. The second material is different from the first material. ## Claims ### Claim 1 A variable resistance element, comprising: a first conductive layer including a first element including at least one selected from the group consisting of silver, copper, aluminum, nickel, and titanium; a second conductive layer including at least one selected from the group consisting of platinum, gold, iridium, tungsten, palladium, rhodium, titanium nitride, and silicon; a first layer contacting the first conductive layer, being provided between the first conductive layer and the second conductive layer, and including a first material, the first material being insulative; and a second layer including a second element and a second material and being provided between the first layer and the second conductive layer, the second element including at least one selected from the group consisting of silver, copper, aluminum, nickel, and titanium, the second material being different from the first material, wherein a thickness of the first layer is thinner than a thickness of the second layer. ### Claim 2 (depends on 1) The variable resistance element according to claim 1, wherein the second material includes an oxide. ### Claim 3 (depends on 1) The variable resistance element according to claim 1, wherein an electron affinity of the first material is smaller than an electron affinity of the second material. ### Claim 4 (depends on 2) The variable resistance element according to claim 2, wherein the first material includes an oxide including at least one selected from the group consisting of Si, Mg, Ca, Hf, Zr, Sc, Ga, Al, Y, La, and Ce, and the oxide included in the second material includes at least one selected from the group consisting of Ta, Nb, Mo, V, Cu, Fe, Mn, Ge, Zn, Gd, and W. ### Claim 5 (depends on 2) The variable resistance element according to claim 2, wherein the first material includes an oxide including at least one selected from the group consisting of Si, Mg, Ca, Al, Y, La, and Ce, and the oxide included in the second material includes at least one selected from the group consisting of Hf, Zr, Sc, and Ga. ### Claim 6 (depends on 2) The variable resistance element according to claim 2, wherein the first material includes an oxide including at least one selected from the group consisting of Si, Mg, and Ca, and the oxide included in the second material includes at least one selected from the group consisting of Al, Y, La, and Ce. ### Claim 7 (depends on 1) The variable resistance element according to claim 1, wherein a relative dielectric constant of the first material is higher than a relative dielectric constant of the second material. ### Claim 8 (depends on 1) The variable resistance element according to claim 1, wherein a concentration of the second element in the second layer is 1×1020 atoms/cm3 or more. ### Claim 9 (depends on 1) The variable resistance element according to claim 1, wherein the first material includes aluminum oxide. ### Claim 10 (depends on 1) The variable resistance element according to claim 1, wherein the second material includes hafnium oxide. ### Claim 11 (depends on 1) The variable resistance element according to claim 1, wherein a thickness of the first layer is not less than 0.2 nanometers and not more than 1.5 nanometers, and a thickness of the second layer is greater than 1.5 nanometers and not more than 10 nanometers. ### Claim 12 (depends on 1) The variable resistance element according to claim 1, wherein the first material includes aluminum oxide, the second material includes hafnium oxide, the first layer does not include the second element, or the first layer includes the second element, and a concentration of the second element in the second layer is higher than a concentration of the second element in the first layer. ### Claim 13 (depends on 1) A memory device, comprising: the variable resistance element according to claim 1; a first interconnect electrically connected to the first conductive layer; a second interconnect electrically connected to the second conductive layer; and a controller electrically connected to the first interconnect and the second interconnect, the controller implementing: a first operation of applying a first voltage to the first interconnect, the first voltage being positive when referenced to a potential of the second interconnect, a second operation of applying a second voltage to the first interconnect, the second voltage being negative when referenced to the potential of the second interconnect, and a third operation of applying a third voltage to the first interconnect, the third voltage being smaller than the first voltage and being positive when referenced to the potential of the second interconnect, the absolute value of a first current flowing in a stacked body via the first interconnect and the second interconnect in the third operation implemented after the first operation is greater than the absolute value of a second current flowing in the stacked body in the third operation implemented after the second operation, the stacked body including the first conductive layer, the second conductive layer, the first layer, and the second layer, and the absolute value of a fourth current flowing in the stacked body via the first interconnect and the second interconnect when a fourth voltage is applied to the first interconnect is greater than the absolute value of a fifth current flowing in the stacked body via the first interconnect and the second interconnect when a fifth voltage is applied to the first interconnect, the fourth voltage being positive when referenced to the potential of the second interconnect, the fifth voltage being negative when referenced to the potential of the second interconnect, the fourth voltage being ⅓ of the third voltage, the absolute value of the fifth voltage being ⅓ of the third voltage. ### Claim 14 (depends on 13) The device according to claim 13, wherein the absolute value of the first voltage is less than the absolute value of the second voltage. ### Claim 15 (depends on 13) The device according to claim 13, wherein the absolute value of the first current is not less than 100 times the absolute value of the fourth current. ### Claim 16 (depends on 13) The device according to claim 13, wherein the absolute value of the fifth voltage is less than ⅓ of the absolute value of the second voltage. ### Claim 17 A variable resistance element, comprising: a first conductive layer including a first element including at least one selected from the group consisting of silver, copper, aluminum, nickel, and titanium; a second conductive layer including at least one selected from the group consisting of platinum, gold, iridium, tungsten, palladium, rhodium, titanium nitride, and silicon; a first layer contacting the first conductive layer, being provided between the first conductive layer and the second conductive layer, and including a first material, the first material being insulative; and a second layer including a second element and a second material and being provided between the first layer and the second conductive layer, the second element including at least one selected from the group consisting of silver, copper, aluminum, nickel, and titanium, the second material being different from the first material, wherein the first layer does not include the second element, or the first layer includes the second element, and a concentration of the second element in the second layer is higher than a concentration of the second element in the first layer. ### Claim 18 (depends on 17) The variable resistance element according to claim 17, wherein the second material includes an oxide. ### Claim 19 (depends on 17) The variable resistance element according to claim 17, wherein an electron affinity of the first material is smaller than an electron affinity of the second material. ### Claim 20 (depends on 18) The variable resistance element according to claim 18, wherein the first material includes an oxide including at least one selected from the group consisting of Si, Mg, Ca, Hf, Zr, Sc, Ga, Al, Y, La, and Ce, and the oxide included in the second material includes at least one selected from the group consisting of Ta, Nb, Mo, V, Cu, Fe, Mn, Ge, Zn, Gd, and W. ### Claim 21 (depends on 18) The variable resistance element according to claim 18, wherein the first material includes an oxide including at least one selected from the group consisting of Si, Mg, Ca, Al, Y, La, and Ce, and the oxide included in the second material includes at least one selected from the group consisting of Hf, Zr, Sc, and Ga. ### Claim 22 (depends on 18) The variable resistance element according to claim 18, wherein the first material includes an oxide including at least one selected from the group consisting of Si, Mg, and Ca, and the oxide included in the second material includes at least one selected from the group consisting of Al, Y, La, and Ce. ### Claim 23 (depends on 17) The variable resistance element according to claim 17, wherein a relative dielectric constant of the first material is higher than a relative dielectric constant of the second material. ### Claim 24 (depends on 17) The variable resistance element according to claim 17, wherein a concentration of the second element in the second layer is 1×1020 atoms/cm3 or more. ### Claim 25 (depends on 17) The variable resistance element according to claim 17, wherein the first material includes aluminum oxide. ### Claim 26 (depends on 17) The variable resistance element according to claim 17, wherein the second material includes hafnium oxide. ### Claim 27 (depends on 17) The variable resistance element according to claim 17, wherein a thickness of the first layer is not less than 0.2 nanometers and not more than 1.5 nanometers, and a thickness of the second layer is greater than 1.5 nanometers and not more than 10 nanometers. ### Claim 28 (depends on 17) The variable resistance element according to claim 17, wherein the first material includes aluminum oxide, the second material includes hafnium oxide, the first layer does not include the second element, or the first layer includes the second element, and a concentration of the second element in the second layer is higher than a concentration of the second element in the first layer. ### Claim 29 (depends on 17) A memory device, comprising: the variable resistance element according to claim 17, a first interconnect electrically connected to the first conductive layer; a second interconnect electrically connected to the second conductive layer; and a controller electrically connected to the first interconnect and the second interconnect, the controller implementing: a first operation of applying a first voltage to the first interconnect, the first voltage being positive when referenced to a potential of the second interconnect, a second operation of applying a second voltage to the first interconnect, the second voltage being negative when referenced to the potential of the second interconnect, and a third operation of applying a third voltage to the first interconnect, the third voltage being smaller than the first voltage and being positive when referenced to the potential of the second interconnect, the absolute value of a first current flowing in a stacked body via the first interconnect and the second interconnect in the third operation implemented after the first operation is greater than the absolute value of a second current flowing in the stacked body in the third operation implemented after the second operation, the stacked body including the first conductive layer, the second conductive layer, the first layer, and the second layer, and the absolute value of a fourth current flowing in the stacked body via the first interconnect and the second interconnect when a fourth voltage is applied to the first interconnect is greater than the absolute value of a fifth current flowing in the stacked body via the first interconnect and the second interconnect when a fifth voltage is applied to the first interconnect, the fourth voltage being positive when referenced to the potential of the second interconnect, the fifth voltage being negative when referenced to the potential of the second interconnect, the fourth voltage being ⅓ of the third voltage, the absolute value of the fifth voltage being ⅓ of the third voltage. ### Claim 30 A variable resistance element, comprising: a first conductive layer including a first element including at least one selected from the group consisting of silver, copper, aluminum, nickel, and titanium; a second conductive layer including at least one selected from the group consisting of platinum, gold, iridium, tungsten, palladium, rhodium, titanium nitride, and silicon; a first layer contacting the first conductive layer, being provided between the first conductive layer and the second conductive layer, and including a first material, the first material being insulative; and a second layer including a second element and a second material and being provided between the first layer and the second conductive layer, the second element including at least one selected from the group consisting of silver, copper, aluminum, nickel, and titanium, the second material being different from the first material, wherein the second layer includes a first region and a second region, the second region being provided between the first region and the second conductive layer, and a concentration of the second element included in the first region is lower than a concentration of the second element included in the second region.