# US 7,745,874 B2 · Floating gate having multiple charge storing layers, method of fabricating the floating gate, non-volatile memory device using the same, and fabricating method thereof > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,745,874 B2 - Document ID: US7745874B2 - Status: Granted - Kind: B2 - Application number: 11/907,639 - Filed: 2007-10-16 - Published: 2009-04-02 - Granted: 2010-06-29 - Earliest claimed: 2007-09-27 - Assignees: Kookmin University Industry Academy Cooperation Foundation - Inventors: Jang-Sik Lee; Jinhan Cho; Jaegab Lee - Web page: https://patentgrep.com/patent/US7745874B2 ## CPC - H10D 30/6893: {wherein the floating gate has multiple non-connected parts, e.g. multi-particle floating gate} - B82Y 10/00: Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic - H10D 30/697: {having trapping at multiple separated sites, e.g. multi-particles trapping sites} - H10D 64/035: {comprising conductor-insulator-conductor-insulator-semiconductor structures} - H10D 64/037: {comprising charge-trapping insulators} - H10D 64/685: {being perpendicular to the channel plane} - H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES - B82Y: SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES ## Abstract Provided is a floating gate having multiple charge storing layers, a non-volatile memory device using the same, and a method of fabricating the floating gate and the non-volatile memory device, in which the multiple charge storing layers using metal nano-crystals of nano size is formed to thereby enhance a charge storage capacity of the memory device. The floating gate includes a polymer electrolytic film which is deposited on a tunneling oxide film, and is formed of at least one stage in which at least one thin film is deposited on each stage, and at least one metal nano-crystal film which is self-assembled on the upper surface of each stage of the polymer electrolytic film and on which a number of metal nano-crystals for trapping charges are deposited. The floating gate is made by self-assembling the metal nano-crystals on the polymer electrolytic film, and thus can be fabricated without undergoing a heat treatment process at high temperature. ## Claims ### Claim 1 A floating gate formed between a tunneling oxide film and a control oxide film in order to store charges, for use in a non-volatile memory device, the floating gate comprising: a polymer electrolytic film formed on the tunneling oxide film, and including at least one stage wherein at least one layer is deposited on each stage, the at least one layer defining an electrically charged surface; and at least one charge trap layer of metal nano-particles adsorbed on the electrically charged surface of each stage of the polymer electrolytic film. ### Claim 2 (depends on 1) The floating gate according to claim 1, wherein the polymer electrolytic film of each stage is formed by laminating a first electrolytic film having a positive charge and a second electrolytic film having a negative charge alternately in a multi-stage, and the metal nano-particles are combined using any one method among an electrostatic attraction force, a hydrogen bond and a covalent bond. ### Claim 3 (depends on 1) The floating gate according to claim 1, wherein the tunneling oxide film and the control oxide film are made of at least one selected from the group consisting of silicon oxide (SiO2), aluminum oxide (Al2O3), zirconium oxide, zirconium silicate, hafnium oxide (HfO2), and hafnium silicate. ### Claim 4 A non-volatile memory device comprising: a substrate; a tunneling oxide film formed on the substrate; at least one polymer electrolytic film formed on the tunneling oxide film, the polymer electrolytic film defining an electrically charged upper surface; at least one charge trap layer formed of a plurality of metal nano-particles adsorbed on the electrically charged upper surface of the polymer electrolytic film; a control oxide film formed on an upper part of the charge trap layer; and a control gate formed on the control oxide film. ### Claim 5 (depends on 4) The non-volatile memory device according to claim 4, wherein the polymer electrolytic film is made of at least one layer. ### Claim 6 (depends on 4) The non-volatile memory device according to claim 4, wherein the polymer electrolytic film is formed of a thin film made of any one selected from the group consisting of an amine group, a sulfonic acid (SO3−) group and a carboxylic acid (COO−) group. ### Claim 7 (depends on 4) The non-volatile memory device according to claim 4, wherein the polymer electrolytic film is formed by laminating a first electrolytic film having a positive charge and a second electrolytic film having a negative charge alternately in a multi-stage, to adsorb the metal nano-particles by a self assembly method. ### Claim 8 (depends on 7) The non-volatile memory device according to claim 7, wherein the metal nano-particles are set to have a charge polarity reverse to that of the polymer electrolytic film which is located at the uppermost layer of the polymer electrolytic film. ### Claim 9 (depends on 4) The non-volatile memory device according to claim 4, wherein an adsorption between the metal nano-particles and the polymer electrolytic film is accomplished by any one among an electrostatic attraction force, a hydrogen bond and a covalent bond. ### Claim 10 (depends on 4) The non-volatile memory device according to claim 4, wherein the metal nano-particles are made of any one selected from the group consisting of Co, Fe, Ni, Cr, Au, Ag, Cu, Al, Pt, Sn, W, Ru, Pd and Cd. ### Claim 11 (depends on 4) The non-volatile memory device according to claim 4, wherein the at least one polymer electrolytic film and the at least one charge trap layer form a floating gate storing charges. ### Claim 12 A non-volatile memory device comprising: a substrate; a tunneling oxide film formed on the substrate; at least one polymer electrolytic film formed on the tunneling oxide film, the polymer electrolytic film being charged; at least one charge trap layer made up of a number of metal nano-particles and adsorbed on an upper surface of the polymer electrolytic film; a control oxide film formed on an upper part of the charge trap layer; and a control gate formed on the control oxide film; a floating gate being formed by the at least one polymer electrolytic film and the at least one charge trap layer; wherein the floating gate is formed with a structure that includes sequentially formed poly(allylamine), poly(styrenesulfonate), poly(allylamine) layers, and said charge trap layer made of a number of gold nano-particles having negative charge. ### Claim 13 A non-volatile memory device comprising: a semiconductor substrate; a tunneling oxide film formed on the semiconductor substrate; a floating gate formed on the tunneling oxide film to store charges selectively; a control oxide film formed on an upper part of the charge trap layer; and a control gate formed on the control oxide film, wherein the floating gate comprises: at least one stage of the polymer electrolytic film formed on the tunneling oxide film, the polymer electrolytic film defining an electrically charged upper surface to adsorb and support metal nano-particles; and, at least one charge trap layer including a plurality of metal nano-particles adsorbed on the electrically charged upper surface of each stage of the polymer electrolytic film. ### Claim 14 (depends on 13) The non-volatile memory device according to claim 13, wherein the polymer electrolytic film of each stage is formed of a structure that two polymer electrolytic films whose surface charge polarities differ from each other are laminated. ### Claim 15 (depends on 1) The floating gate according to claim 1, wherein the polymer electrolytic film includes a plurality of layers, adjacent ones of the layers being electrically charged to be opposed in polarity. ### Claim 16 (depends on 15) The floating gate according to claim 15, wherein adjacent ones of the layers are formed of different materials. ### Claim 17 (depends on 4) The non-volatile memory device according to claim 4, wherein the polymer electrolytic film includes a plurality of layers, adjacent ones of the layers being electrically charged to be opposed in polarity. ### Claim 18 (depends on 17) The non-volatile memory device according to claim 17, wherein adjacent ones of the layers are formed of different materials. ### Claim 19 (depends on 13) The non-volatile memory device according to claim 13, wherein the polymer electrolytic film includes a plurality of layers, adjacent ones of the layers being electrically charged to be opposed in polarity. ### Claim 20 (depends on 19) The non-volatile memory device according to claim 19, wherein adjacent ones of the layers are formed of different materials.