Semiconductor Energy Laboratory Co., Ltd.

Hajime Tokunaga

Junichi Koezuka

Yukinori Shima

Toshinari Sasaki

Daisuke Matsubayashi

Keisuke Murayama

Shunpei Yamazaki

Masami Jintyou

Yasutaka Nakazawa

Takahiro Sato

Shunsuke Koshioka

Takayuki Cho

Takuya Handa

Kenichi Okazaki

Kiyoshi Kato

Ryota Tajima

Toshihiko Saito

Naoki Okuno

Akihisa Shimomura

Tetsuji Yamaguchi

Hiromichi Godo

Mitsuo Mashiyama

Masahiro Watanabe

Toru Takayama

Kengo Akimoto

Ryoji Nomura

To reduce defects in an oxide semiconductor film in a semiconductor device. To improve the electrical characteristics and the reliability of a semiconductor device including an oxide semiconductor film. In a semiconductor device including a transistor including a gate electrode formed over a substrate, a gate insulating film covering the gate electrode, a multilayer film overlapping with the gate electrode with the gate insulating film provided therebetween, and a pair of electrodes in contact with the multilayer film, a first oxide insulating film covering the transistor, and a second oxide insulating film formed over the first oxide insulating film, the multilayer film includes an oxide semiconductor film and an oxide film containing In or Ga, the first oxide insulating film is an oxide insulating film through which oxygen is permeated, and the second oxide insulating film is an oxide insulating film containing more oxygen than that in the stoichiometric composition.

Semiconductor device and method for manufacturing the same

A transistor includes a multilayer film in which an oxide semiconductor film and an oxide film are stacked, a gate electrode, and a gate insulating film. The multilayer film overlaps with the gate electrode with the gate insulating film interposed therebetween. The multilayer film has a shape having a first angle between a bottom surface of the oxide semiconductor film and a side surface of the oxide semiconductor film and a second angle between a bottom surface of the oxide film and a side surface of the oxide film. The first angle is acute and smaller than the second angle. Further, a semiconductor device including such a transistor is manufactured.

Semiconductor device

In a semiconductor device including a transistor including a gate electrode formed over a substrate, a gate insulating film covering the gate electrode, a multilayer film overlapping with the gate electrode with the gate insulating film provided therebetween, and a pair of electrodes in contact with the multilayer film, a first oxide insulating film covering the transistor, and a second oxide insulating film formed over the first oxide insulating film, the multilayer film includes an oxide semiconductor film and an oxide film containing In or Ga, the oxide semiconductor film has an amorphous structure or a microcrystalline structure, the first oxide insulating film is an oxide insulating film through which oxygen is permeated, and the second oxide insulating film is an oxide insulating film containing more oxygen than that in the stoichiometric composition.

Stable electrical characteristics of a transistor including an oxide semiconductor layer are achieved. A highly reliable semiconductor device including the transistor is provided. The semiconductor device includes a multilayer film formed of an oxide layer and an oxide semiconductor layer, a gate insulating film in contact with the oxide layer, and a gate electrode overlapping with the multilayer film with the gate insulating film interposed therebetween. The oxide layer contains a common element to the oxide semiconductor layer and has a large energy gap than the oxide semiconductor layer. The composition between the oxide layer and the oxide semiconductor layer gradually changes.

Semiconductor device comprising an oxide layer and an oxide semiconductor layer

To provide a semiconductor device which has transistor characteristics with little variation and includes an oxide semiconductor. The semiconductor device includes an insulating film over a conductive film and an oxide semiconductor film over the insulating film. The oxide semiconductor film includes a first oxide semiconductor layer, a second oxide semiconductor layer over the first oxide semiconductor layer, and a third oxide semiconductor layer over the second oxide semiconductor layer. The energy level of a bottom of a conduction band of the second oxide semiconductor layer is lower than those of the first and third oxide semiconductor layers. An end portion of the second oxide semiconductor layer is positioned on an inner side than an end portion of the first oxide semiconductor layer.

A transistor or the like having high field-effect mobility is provided. A transistor or the like having stable electrical characteristics is provided. A semiconductor device including a first oxide semiconductor layer, a second oxide semiconductor layer, a gate insulating film, and a gate electrode which partly overlap with one another is provided. The second oxide semiconductor layer is positioned between the first oxide semiconductor layer and the gate insulating film. The gate insulating film is positioned between the second oxide semiconductor layer and the gate electrode. The first oxide semiconductor layer has fewer oxygen vacancies than those of the second oxide semiconductor layer.

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Kanagawa, Japan

Hajime Tokunaga