Semiconductor Energy Laboratory Co., Ltd.

Shunsuke Adachi

Takuya Hirohashi

Junichi Koezuka

Shunpei Yamazaki

Satoshi Seo

Kenichi Okazaki

Akiharu Miyanaga

Masahiro Takahashi

Masami Jintyou

Yasuharu Hosaka

Yasutaka Nakazawa

Motoki Nakashima

Toshimitsu Obonai

Takahiro Kawakami

Yohei Momma

Teruaki Ochiai

Mayumi Mikami

Shuhei Yoshitomi

Takeshi Osada

Ryota Tajima

Teppei Oguni

Tetsuya Kakehata

Kunio Hosoya

Tamae Moriwaka

Yumiko Yoneda

Yumiko Saito

In a semiconductor device using a transistor including an oxide semiconductor, a change in electrical characteristics is suppressed and reliability is improved. The semiconductor device includes a gate electrode over an insulating surface; an oxide semiconductor film overlapping with the gate electrode; a gate insulating film that is between the gate electrode and the oxide semiconductor film and in contact with the oxide semiconductor film; a protective film in contact with a surface of the oxide semiconductor film that is an opposite side of a surface in contact with the gate insulating film; and a pair of electrodes in contact with the oxide semiconductor film. The spin density of the gate insulating film or the protective film measured by electron spin resonance spectroscopy is lower than 1&#xd7;10spins/cm, preferably higher than or equal to 1&#xd7;10spins/cmand lower than 1&#xd7;10spins/cm.

Semiconductor device

A semiconductor device including a transistor having a reduced number of oxygen vacancies in a channel formation region of an oxide semiconductor with stable electrical characteristics or high reliability is provided. A gate insulating film is formed over a gate electrode; an oxide semiconductor layer is formed over the gate insulating film; an oxide layer is formed over the oxide semiconductor layer by a sputtering method to form an stacked-layer oxide film including the oxide semiconductor layer and the oxide layer; the stacked-layer oxide film is processed into a predetermined shape; a conductive film containing Ti as a main component is formed over the stacked-layer oxide film; the conductive film is etched to form source and drain electrodes and a depression portion on a back channel side; and portions of the stacked-layer oxide film in contact with the source and drain electrodes are changed to an n-type by heat treatment.

A lithium secondary battery which has high charge-discharge capacity, can be charged and discharged at high speed, and has little deterioration in battery characteristics due to charge and discharge is provided. A negative electrode includes a current collector and a negative electrode active material layer. The current collector includes a plurality of protrusion portions extending in a substantially perpendicular direction and a base portion connected to the plurality of protrusion portions. The protrusion portions and the base portion are formed using the same material containing titanium. A top surface of the base portion and at least a side surface of the protrusion portion are covered with the negative electrode active material layer. The negative electrode active material layer may be covered with graphene.

Negative electrode for lithium secondary battery, lithium secondary battery, and manufacturing methods thereof

To increase the amount of lithium ions that can be received in and released from a positive electrode active material to achieve high capacity and high energy density of a secondary battery. A lithium manganese oxide particle includes a first region and a second region. The valence number of manganese in the first region is lower than the valence number of manganese in the second region. The lithium manganese oxide has high structural stability and high capacity characteristics.

Lithium-manganese composite oxide and secondary battery

With a small amount of a conductive additive, an electrode for a storage battery including an active material layer which is highly filled with an active material is provided. The use of the electrode enables fabrication of a storage battery having high capacity per unit volume of the electrode. By using graphene as a conductive additive in an electrode for a storage battery including a positive electrode active material, a network for electron conduction through graphene is formed. Consequently, the electrode can include an active material layer in which particles of an active material are electrically connected to each other by graphene. Therefore, graphene is used as a conductive additive in an electrode for a sodium-ion secondary battery including an active material with low electric conductivity, for example, an active material with a band gap of 3.0 eV or more.

Sodium-ion secondary battery

A method for manufacturing a semiconductor device including a transistor with stable electrical characteristics or high reliability is provided. A gate insulating film is formed over a gate electrode; an oxide semiconductor layer is formed over the gate insulating film; an oxide layer is formed over the oxide semiconductor layer to form a stacked-layer oxide film including the oxide semiconductor layer and the oxide layer; the stacked-layer oxide film is processed into a predetermined shape; a conductive film containing Ti is formed over the stacked-layer oxide film; the conductive film is etched to form source and drain electrodes; and regions in the oxide layer in contact with the source and drain electrodes are heat treated so as to have a low resistivity.

Method for manufacturing semiconductor device

The amount of lithium ions that can be received and released in and from a positive electrode active material is increased, and high capacity and high energy density of a secondary battery are achieved. Provided is a lithium-manganese composite oxide represented by LiMnMO, where M is a metal element other than Li and Mn, or Si or P, and y, z, and w satisfy 0&#x2266;x/(y+z)&#x3c;2, y&#x3e;0, z&#x3e;0, 0.26&#x2266;(y+z)/w&#x3c;0.5, and 0.2&#x3c;z/y&#x3c;1.2. The lithium manganese composite oxide has high structural stability and high capacity.

Lithium&#x2014;manganese composite oxide, secondary battery, and electric device

Growing community of inventors

Kanagawa, Japan

Shunsuke Adachi