Abstract: A manufacturing method of a semiconductor device includes the forming a first oxide over a substrate; depositing a first insulator over the first oxide; forming an opening reaching the first oxide in the first insulator; depositing a first oxide film in contact with the first oxide and the first insulator in the opening; depositing a first insulating film over the first oxide film by a PEALD method; depositing a first conductive film over the first insulating film; and removing part of the first oxide film, part of the first insulating film, and part of the first conductive film until a top surface of the first insulator is exposed to form a second oxide, a second insulator, and a first conductor. The deposition of the first insulating film is performed while the substrate is heated to higher than or equal to 300°.

Abstract: An object of one embodiment of the present invention is to achieve a manufacturing method which can increase capacity density of a secondary battery. Another object is to provide a manufacturing method of a highly safe or reliable secondary battery. The manufacturing method of electrodes (a positive electrode and a negative electrode) of a secondary battery includes a vibration treatment step for supplying vibration to the electrode and a press step for applying pressure to the electrode to compress an active material layer in the electrode. The vibration treatment step is performed before the press step.

Abstract: A novel method for forming a positive electrode active material is provided. In the method for forming a positive electrode active material, a cobalt source and an additive element source are mixed to form an acidic solution; the acidic solution and an alkaline solution are made to react to form a cobalt compound; the cobalt compound and a lithium source are mixed to form a mixture; and the mixture is heated. The additive element source is a compound containing one or more selected from gallium, aluminum, boron, nickel, and indium.

Abstract: A positive electrode active material having a high charge-discharge capacity and high safety and a secondary battery including the positive electrode active material are provided. The positive electrode active material includes lithium, a transition metal M, an additive element, and oxygen. The powder volume resistivity of the positive electrode active material is higher than or equal to 1.0×105 ?·cm at a temperature of higher than or equal to 180° C. and lower than or equal to 200° C. and at a pressure of higher than or equal to 0.3 MPa and lower than or equal to 2 MPa. The median diameter of the positive electrode active material is preferably greater than or equal to 3 ?m and less than or equal to 10 ?m.

Abstract: A positive electrode and a secondary battery with little deterioration due to charge and discharge are provided. A positive electrode and a secondary battery with high electrode density are provided. Alternatively, a positive electrode and a secondary battery with excellent rate characteristics are provided. The positive electrode contains a positive electrode active material and a coating material. The coating material covers at least part of a surface of the positive electrode active material, and the positive electrode active material contains lithium cobalt oxide containing magnesium, fluorine, aluminum, and nickel. The lithium cobalt oxide includes a region with the highest concentration of one or more selected from the magnesium, the fluorine, and the aluminum in a surface portion. The coating material is preferably one or more selected from glass, carbon black, graphene, and a graphene compound.

Abstract: A novel method for forming a metal oxide is provided. The metal oxide is formed using a precursor with a high decomposition temperature while a substrate is heated to higher than or equal to 300° C. and lower than or equal to 500° C. In the formation, plasma treatment, microwave treatment, or heat treatment is preferably performed as impurity removal treatment in an atmosphere containing oxygen. The impurity removal treatment may be performed while irradiation with ultraviolet light is performed. The metal oxide is formed by alternate repetition of precursor introduction and oxidizer introduction. For example, the impurity removal treatment is preferably performed every time the precursor introduction is performed more than or equal to 5 times and less than or equal to 10 times.

Abstract: A secondary battery stable in a high-potential state and/or a high-temperature state is provided. The secondary battery includes a positive electrode and a negative electrode, and one or both of the positive electrode and the negative electrode contain an active material and a composite compound with a crystal structure. The composite compound has a function of a binder. The composite compound can also be used as an electrolyte. The composite compound with a crystal structure has typically a molecular crystal. The composite compound with a crystal structure can be obtained by mixing a first compound and a second compound while heating is performed at higher than or equal to a temperature at which a mixture of the first compound and the second compound is melted.

Abstract: A positive electrode active material that is stable in a high potential state or a high temperature state and a highly safe secondary battery are provided. The positive electrode includes a first material and a second material and includes a region where at least part of a surface of the first material is covered with the second material. The first material includes a lithium cobalt oxide containing magnesium, fluorine, aluminum, and nickel. The second material includes a composite oxide (containing one or more selected from Fe, Ni, Co, and Mn) having an olivine crystal structure.

Abstract: A semiconductor device with high on-state current and high reliability is provided. The semiconductor device includes first to fifth insulators, first to third oxides, and first to fourth conductors; the fifth insulator includes an opening in which the second oxide is exposed; the third oxide is placed in contact with a bottom portion of the opening and a side portion of the opening; the second insulator is placed in contact with the third oxide; the third conductor is provided in contact with the second insulator; the third insulator is placed in contact with a top surface of the third conductor and the second insulator; and the fourth conductor is in contact with the third insulator and the top surface of the third conductor and placed in the opening.

Abstract: A method for manufacturing a highly purified positive electrode active material is provided. Alternatively, a method for manufacturing a positive electrode active material whose crystal structure is not easily broken even when charge and discharge are repeated is provided. The method for manufacturing a positive electrode active material containing lithium and a transition metal includes a first step of preparing a lithium compound, a phosphorus compound, and water; a second step of forming a first mixture by mixing the lithium compound, the phosphorus compound, and the water; a third step of forming a second mixture by adding a first aqueous solution to the first mixture to adjust a pH; a fourth step of forming a third mixture by mixing an iron(II) compound with the second mixture; a fifth step of forming a fourth mixture by heating the third mixture; and a sixth step of obtaining a positive electrode active material by filtering, washing, and drying the fourth mixture.

Abstract: A lithium ion battery having excellent charge characteristics and discharge characteristics even in a low-temperature environment is provided. The lithium ion battery includes a positive electrode active material and an electrolyte. The positive electrode active material contains cobalt, oxygen, magnesium, aluminum, and nickel. The electrolyte contains lithium hexafluorophosphate, ethylene carbonate, ethyl methyl carbonate, and dimethyl carbonate. Second discharge capacity of the lithium ion battery is higher than or equal to 70% of first discharge capacity. The first discharge capacity is obtained by performing first charge and first discharge at 20° C., and the second discharge capacity is obtained by performing second charge and second discharge at ?40° C. The first discharge and the second discharge are constant current discharge with 20 mA/g per positive electrode active material weight.

Abstract: A method of forming a highly purified positive electrode active material is provided. A method of forming a positive electrode active material whose crystal structure is not easily broken even when charge and discharge are repeated is provided. The method of forming a positive electrode active material including lithium and a transition metal includes a first step of preparing a lithium source and a transition metal source and a second step of crushing and mixing the lithium source and the transition metal source to form a composite material. In the first step, a material with a purity of greater than or equal to 99.99% is prepared as the lithium source and a material with a purity of greater than or equal to 99.9% is prepared as the transition metal source. In the second step, crushing and mixing are performed using dehydrated acetone.

Abstract: A manufacturing method of a highly purified positive electrode active material is provided. Alternatively, a manufacturing method of a positive electrode active material whose crystal structure is not easily broken even when charging and discharging are repeated is provided. Provided is a manufacturing method of a positive electrode active material containing lithium and a transition metal. The manufacturing method includes a first step of forming a hydroxide containing the transition metal using a basic aqueous solution and an aqueous solution containing the transition metal, a second step of preparing a lithium compound, a third step of mixing the lithium compound and the hydroxide to form a mixture, and a fourth step of heating the mixture to form a composite oxide containing lithium and the transition metal. A material with a purity higher than or equal to 99.

Abstract: A semiconductor device having favorable electrical characteristics is provided. A metal oxide is formed over a substrate by the steps of: introducing a first precursor into a chamber in which the substrate is provided; introducing a first oxidizer after the introduction of the first precursor; introducing a second precursor after the introduction of the first oxidizer; and introducing a second oxidizer after the introduction of the second precursor.

Abstract: One embodiment of the present invention achieves a fabrication method that can automate fabrication of a secondary battery. In addition, a fabrication method that can fabricate a secondary battery efficiently in a short time is achieved. Furthermore, a fabrication method that can fabricate a secondary battery with high yield is achieved. Alternatively, a method for fabricating a large secondary battery with a relatively large size is achieved. An electrolyte is dripped on one or more of a positive electrode, a separator, and a negative electrode; the one or more of the positive electrode, the separator, and the negative electrode are impregnated with the electrolyte; pressure is then reduced; and a stack of the positive electrode, the separator, and the negative electrode is sealed with an exterior film.

Abstract: A semiconductor device with high on-state current and high reliability is provided. The semiconductor device includes first to fifth insulators, first to third oxides, and first to fourth conductors; the fifth insulator includes an opening in which the second oxide is exposed; the third oxide is placed in contact with a bottom portion of the opening and a side portion of the opening; the second insulator is placed in contact with the third oxide; the third conductor is provided in contact with the second insulator; the third insulator is placed in contact with a top surface of the third conductor and the second insulator; and the fourth conductor is in contact with the third insulator and the top surface of the third conductor and placed in the opening.

Abstract: A semiconductor device with a small variation in characteristics is provided. The semiconductor device includes an oxide, a first conductor and a second conductor over the oxide, a first insulator over the first conductor, a second insulator over the second conductor, a third insulator over the first insulator and the second insulator, a fourth insulator over the third insulator, a fifth insulator that is over the oxide and is located between the first conductor and the second conductor; a sixth insulator over the fifth insulator; a seventh insulator over the sixth insulator, and a third conductor over the seventh insulator. The third conductor includes a region overlapping with the oxide, the fifth insulator has a region that is in contact with each of the oxide, the first conductor, the second conductor, and the first to fourth insulators, and the sixth insulator contains hydrogen, nitrogen, oxygen, and silicon.

Abstract: A novel deposition method of a metal oxide is provided. The deposition method includes a first step of supplying a first precursor to a chamber; a second step of supplying a second precursor to the chamber; a third step of supplying a third precursor to the chamber; and a fourth step of introducing an oxidizer into the chamber after the first step, the second step, and the third step. The first to third precursors are different kinds of precursors, and a substrate placed in the chamber in the first to fourth steps is heated to a temperature higher than or equal to 300° C. and lower than or equal to decomposition temperatures of the first to third precursors.

Abstract: A semiconductor device having favorable electrical characteristics is provided. A metal oxide is formed over a substrate by the steps of: introducing a first precursor into a chamber in which the substrate is provided; introducing a first oxidizer after the introduction of the first precursor; introducing a second precursor after the introduction of the first oxidizer; and introducing a second oxidizer after the introduction of the second precursor.

Abstract: To provide a highly reliable memory device.