# US 9,437,704 B2 · Semiconductor device having electrode made of high work function material, method and apparatus for manufacturing the same > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,437,704 B2 - Document ID: US9437704B2 - Status: Granted - Kind: B2 - Application number: 14/629,345 - Filed: 2015-02-23 - Published: 2015-06-18 - Granted: 2016-09-06 - Earliest claimed: 2010-01-07 - Assignees: Hitachi Kokusai Electric Inc. - Applicants: Hitachi Kokusai Electric Inc. - Inventors: Sadayoshi Horii; Arito Ogawa; Hideharu Itatani - Web page: https://patentgrep.com/patent/US9437704B2 ## CPC - H10D 64/01318: {the conductor comprising a layer of alloy material, compound material or organic material contacting the insulator, e.g. TiN (comprising a layer of alloys of Si, Ge or C H10D64/01314)} - C23C 16/06: characterised by the deposition of metallic material - C23C 16/34: Nitrides {(C23C16/303 takes precedence)} - C23C 16/45529: {specially adapted for making a layer stack of alternating different compositions or gradient compositions} - H10D 1/696: {comprising multiple layers, e.g. comprising a barrier layer and a metal layer (barrier layers to prevent diffusion of hydrogen or oxygen in perovskite based capacitors H10D1/688)} - H10D 64/01342: {by deposition, e.g. evaporation, ALD or laser deposition (H10D64/01344 takes precedence)} - H10D 64/667: {the conductor comprising a layer of alloy material, compound material or organic material contacting the insulator, e.g. TiN workfunction layers (having lateral variation H10D64/671)} - H10D 64/669: {the conductor further comprising additional layers of alloy material, compound material or organic material, e.g. TaN/TiAlN} - H10D 64/691: {comprising metallic compounds, e.g. metal oxides or metal silicates (insulators comprising nitrogen H10D64/693)} - H10W 20/046: {the barrier, adhesion or liner layers being associated with interconnections of capacitors} - H10W 20/496: {Capacitor integral with wiring layers} - H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES - C23C: COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL (making metal-coated products by extrusion B21C23/22; covering with metal by connecting pre-existing layers to articles, see the relevant places, e.g. B21D39/00, B23K; metallising of glass C03C; metallising mortars, concrete, artificial stone, ceramics or natural stone C04B41/00; enamelling of, or applying a vitreous layer to, metals C23D; treating metal surfaces or coating of metals by electrolysis or electrophoresis C25D; single-crystal film growth C30B; by metallising textiles D06M11/83; decorating textiles by locally metallising D06Q1/04) - H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10 ## Abstract Provided is a semiconductor device including a metal film which can be formed with lower costs but still mange to have a necessary work function and oxidation resistance. The semiconductor device includes an insulating film disposed on a substrate; and a metal film disposed on the insulating film. The metal film includes a stacked structure of: a first metal film disposed on the insulating film to directly contact the insulating film; a second metal film disposed on the first metal film to directly contact the first metal film; and the first metal film disposed on the second metal film to directly contact the second metal film, the second metal film having a work function greater than 4.8 eV and being different from the first metal film in material, wherein an oxidation resistance of the first metal film is greater than that of the second metal film. ## Claims ### Claim 1 A semiconductor device comprising: an insulating film disposed on a substrate; and a metal film comprising a stacked structure of: a laminated film where a first metal film and a second metal film are laminated repeatedly; and a capping metal film disposed on the laminated film, the first metal film at a bottom of the metal film being disposed on the insulating film to directly contact the insulating film, the capping metal film being disposed on the second metal film at a top of the metal film to directly contact the second metal film, the second metal film having a work function greater than 4.8 eV and being different from the first metal film in material, and the capping metal film being constituted by a same material as the first metal film, wherein oxidation resistances of the first metal film and the capping metal film are greater than that of the second metal film. ### Claim 2 (depends on 1) The semiconductor device of claim 1, wherein a thickness of the first metal film ranges from 0.2 nm to 4 nm. ### Claim 3 (depends on 1) The semiconductor device of claim 1, wherein a thickness of the second metal film ranges from 0.5 nm to 10 nm. ### Claim 4 (depends on 1) The semiconductor device of claim 1, wherein a thickness of the second metal film ranges from 4 nm to 5 nm. ### Claim 5 (depends on 1) The semiconductor device of claim 1, wherein the second metal film is thicker than the first metal film. ### Claim 6 (depends on 1) The semiconductor device of claim 1, wherein the first metal film comprises one of a titanium nitride film, a tantalum nitride film, a titanium aluminum nitride film and a tantalum aluminum nitride film. ### Claim 7 (depends on 1) The semiconductor device of claim 1, wherein the second metal m comprises a non-noble metal. ### Claim 8 (depends on 1) The semiconductor device of claim 1, wherein the second metal film comprises at least one of a nickel film, a cobalt film, a beryllium film, a carbon film, a selenium film, a tellurium film and a rhenium film. ### Claim 9 (depends on 1) The semiconductor device of claim 1, wherein the insulating film comprises a high permittivity film. ### Claim 10 (depends on 1) The semiconductor device of claim 1, wherein the insulating film comprises at least one of a hafnium oxide film, a zirconium oxide film, a hafnium oxide film doped with an aluminum, a zirconium oxide film doped with the aluminum, a titanium oxide film, a niobium oxide film, a tantalum oxide film, a strontium titanate film, a barium strontium titanate film and a lead zirconate titanate film. ### Claim 11 A semiconductor device comprising: an insulating film disposed on a substrate; and a metal film comprising a stacked structure of a laminated film where a first metal film and a second metal film are laminated repeatedly; and a third metal film disposed on the laminated film, the first metal film at a bottom of the metal film being disposed on the insulating film to directly contact the insulating film, the third metal film being disposed on the second metal film at a top of the metal film to directly contact the second metal film, the second metal film having a work function greater than 4.8 eV and being different from the first metal film in material, and the third metal being constituted by a same material as the first metal film, wherein oxidation resistances of the first metal film and the third metal film are greater than that of the second metal film.