# US 2014/0154837 A1 · Method for manufacturing semiconductor device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0154837 A1 - Document ID: US20140154837A1 - Status: Published application - Kind: A1 - Application number: 14/094,293 - Filed: 2013-12-02 - Published: 2014-06-05 - Earliest claimed: 2012-12-03 - Assignees: Semiconductor Energy Laboratory Co., Ltd. - Applicants: Semiconductor Energy Laboratory Co., Ltd. - Inventors: Shunpei Yamazaki - Web page: https://patentgrep.com/patent/US20140154837A1 ## CPC - H10D 30/6755: {Oxide semiconductors, e.g. zinc oxide, copper aluminium oxide or cadmium stannate} - H10D 30/6713: {characterised by the properties of the source or drain regions, e.g. compositions or sectional shapes} - H10D 30/6757: {characterised by the structure of the channel, e.g. transverse or longitudinal shape or doping profile (TFTs having channel structures for preventing kink or snapback effects H10D30/6708; TFTs having lightly-doped source or drain extensions H10D30/6715)} - H10P 14/3238: {being insulating materials} - H10P 14/3426: {Oxides} - H10P 14/3434: {being oxide semiconductor materials (Group IIB-VIA semiconductor materials H10P14/3424)} - H10P 14/36: {characterised by treatments done before the formation of the materials} - H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES - H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10 ## Abstract To improve electric characteristics of a semiconductor device including an oxide semiconductor. Alternatively, to improve reliability of a semiconductor device including an oxide semiconductor. In a transistor including a first oxide film, an oxide semiconductor film, a pair of electrodes in contact with the oxide semiconductor film, and a second oxide film in contact with the oxide semiconductor film and the pair of electrodes, oxygen is added to the first oxide film and the second oxide film in contact with the oxide semiconductor film and the pair of electrodes, so that oxygen vacancies are reduced. The oxygen is diffused to the oxide semiconductor film by heat treatment or the like; thus, oxygen vacancies in the oxide semiconductor film are reduced. ## Claims ### Claim 1 A method for manufacturing a semiconductor device comprising the steps of: forming an oxide film over a substrate; adding oxygen to the oxide film; forming an oxide semiconductor film over the oxide film after adding oxygen to the oxide film; performing heat treatment; etching part of the oxide film and part of the oxide semiconductor film; forming a pair of electrodes over the oxide semiconductor film after etching the part of the oxide film and the part of the oxide semiconductor film; forming a gate insulating film over the oxide semiconductor film and the pair of electrodes; and forming a gate electrode over the gate insulating film. ### Claim 2 (depends on 1) The method for manufacturing a semiconductor device, according to claim 1, wherein the oxide semiconductor film comprises at least one of In, Ga and Zn. ### Claim 3 (depends on 1) The method for manufacturing a semiconductor device, according to claim 1, wherein a distance between a bottom of a conduction band of the oxide film and a vacuum level is smaller than a distance between a bottom of a conduction band of the oxide semiconductor film and the vacuum level. ### Claim 4 (depends on 1) The method for manufacturing a semiconductor device, according to claim 1, wherein a difference between energy of a bottom of a conduction band of the oxide film and energy of a bottom of a conduction band of the oxide semiconductor film is greater than or equal to 0.05 eV and less than or equal to 2 eV. ### Claim 5 (depends on 1) The method for manufacturing a semiconductor device, according to claim 1, wherein the oxygen is added to the oxide film by an ion implantation method, an ion doping method, or plasma treatment. ### Claim 6 A method for manufacturing a semiconductor device comprising the steps of: forming a first oxide film over a substrate; adding oxygen to the first oxide film; forming an oxide semiconductor film over the first oxide film after adding oxygen to the first oxide film; etching part of the first oxide film and part of the oxide semiconductor film; forming a pair of electrodes over the oxide semiconductor film after etching the part of the first oxide film and the part of the oxide semiconductor film; forming a second oxide film over the oxide semiconductor film and the pair of electrodes; performing heat treatment after forming the second oxide film; forming a gate insulating film over the second oxide film; and forming a gate electrode over the gate insulating film. ### Claim 7 (depends on 6) The method for manufacturing a semiconductor device, according to claim 6, wherein the oxide semiconductor film comprises at least one of In, Ga and Zn. ### Claim 8 (depends on 6) The method for manufacturing a semiconductor device, according to claim 6, wherein a distance between a bottom of a conduction band of the first oxide film and a vacuum level is smaller than a distance between a bottom of a conduction band of the oxide semiconductor film and the vacuum level, and wherein a distance between a bottom of a conduction band of the second oxide film and the vacuum level is smaller than the distance between the bottom of the conduction band of the oxide semiconductor film and the vacuum level. ### Claim 9 (depends on 6) The method for manufacturing a semiconductor device, according to claim 6, wherein a difference between energy of a bottom of a conduction band of the first oxide film and energy of a bottom of a conduction band of the oxide semiconductor film is greater than or equal to 0.05 eV and less than or equal to 2 eV, and wherein a difference between energy of a bottom of a conduction band of the second oxide film and the energy of the bottom of the conduction band of the oxide semiconductor film is greater than or equal to 0.05 eV and less than or equal to 2 eV. ### Claim 10 (depends on 6) The method for manufacturing a semiconductor device, according to claim 6, wherein the oxygen is added to the first oxide film by an ion implantation method, an ion doping method, or plasma treatment. ### Claim 11 (depends on 6) The method for manufacturing a semiconductor device, according to claim 6, wherein the oxygen is added to the second oxide film by an ion implantation method, an ion doping method, or plasma treatment. ### Claim 12 (depends on 6) The method for manufacturing a semiconductor device, according to claim 6, wherein heat treatment is performed after forming the oxide semiconductor film over the first oxide film and before forming the second oxide film over the oxide semiconductor film and the pair of electrodes. ### Claim 13 A method for manufacturing a semiconductor device comprising the steps of: forming a gate electrode over a substrate; forming a gate insulating film over the gate electrode; forming a first oxide film over the gate insulating film; adding oxygen to the first oxide film; forming an oxide semiconductor film over the first oxide film after adding oxygen to the first oxide film; etching part of the first oxide film and part of the oxide semiconductor film; forming a pair of electrodes over the oxide semiconductor film after etching the part of the first oxide film and the part of the oxide semiconductor film; forming a second oxide film over the pair of the electrodes and the oxide semiconductor film; adding oxygen to the second oxide film; performing heat treatment; and forming an insulating film over the second oxide film to which the oxygen is added. ### Claim 14 (depends on 13) The method for manufacturing a semiconductor device, according to claim 13, wherein the oxide semiconductor film comprises at least one of In, Ga and Zn. ### Claim 15 (depends on 13) The method for manufacturing a semiconductor device, according to claim 13, wherein a distance between a bottom of a conduction band of the first oxide film and a vacuum level is smaller than a distance between a bottom of a conduction band of the oxide semiconductor film and the vacuum level, and wherein a distance between a bottom of a conduction band of the second oxide film and the vacuum level is smaller than the distance between the bottom of the conduction band of the oxide semiconductor film and the vacuum level. ### Claim 16 (depends on 13) The method for manufacturing a semiconductor device, according to claim 13, wherein a difference between energy of a bottom of a conduction band of the first oxide film and energy of a bottom of a conduction band of the oxide semiconductor film is greater than or equal to 0.05 eV and less than or equal to 2 eV, and wherein a difference between energy of a bottom of a conduction band of the second oxide film and the energy of the bottom of the conduction band of the oxide semiconductor film is greater than or equal to 0.05 eV and less than or equal to 2 eV. ### Claim 17 (depends on 13) The method for manufacturing a semiconductor device, according to claim 13, wherein the oxygen is added to the first oxide film by an ion implantation method, an ion doping method, or plasma treatment. ### Claim 18 (depends on 13) The method for manufacturing a semiconductor device, according to claim 13, wherein the oxygen is added to the second oxide film by an ion implantation method, an ion doping method, or plasma treatment. ### Claim 19 (depends on 13) The method for manufacturing a semiconductor device, according to claim 13, wherein heat treatment is performed after forming the oxide semiconductor film over the first oxide film and before forming the second oxide film over the oxide semiconductor film and the pair of electrodes.