Semiconductor Energy Laboratory Co., Ltd.

Ricoh Company, Ltd.

Takayuki Inoue

Shunpei Yamazaki

Yoshiyuki Kurokawa

Masashi Tsubuku

Takayuki Ikeda

Akiharu Miyanaga

Tetsuhiro Tanaka

Daisuke Kawae

Kengo Akimoto

Hiromichi Godo

Yusuke Nonaka

Hiroki Dembo

Yoshitaka Yamamoto

Yasumasa Yamane

Toshihiko Takeuchi

Masami Endo

Erumu Kikuchi

Hideomi Suzawa

Yasuhiko Takemura

Munehiro Kozuma

Suzunosuke Hiraishi

Kiyoshi Kato

Hidekazu Miyairi

Koji Dairiki

Makoto Furuno

Satoshi Kobayashi

Shuhei Yoshitomi

Tomokazu Yokoi

Koki Inoue

Yasuyuki Arai

Junichiro Sakata

Takeshi Osada

Yukie Suzuki

Hiroaki Kobayashi

Akira Masuda

Tamae Moriwaka

Ryosuke Watanabe

Hajime Kubota

Hiroya Uruta

Daisuke Masui

Tetsuro Kutsuwada

Yusuke Kawatsu

Hiroto Inoue

A manufacturing method of a semiconductor device in which the threshold is adjusted to an appropriate value is provided. The semiconductor device includes a semiconductor, a source or drain electrode electrically connected to the semiconductor, a first gate electrode and a second gate electrode between which the semiconductor is sandwiched, an electron trap layer between the first gate electrode and the semiconductor, and a gate insulating layer between the second gate electrode and the semiconductor. By keeping a potential of the first gate electrode higher than a potential of the source or drain electrode for 1 second or more while heating, electrons are trapped in the electron trap layer. Consequently, threshold is increased and Icut is reduced.

Semiconductor device and method for manufacturing semiconductor device

An object is to manufacture a semiconductor device including an oxide semiconductor film, which has stable electric characteristics and high reliability. A crystalline oxide semiconductor film is formed, without performing a plurality of steps, as follows: by utilizing a difference in atomic weight of plural kinds of atoms included in an oxide semiconductor target, zinc with low atomic weight is preferentially deposited on an oxide insulating film to form a seed crystal including zinc; and tin, indium, or the like with high atomic weight is deposited on the seed crystal while causing crystal growth. Further, a crystalline oxide semiconductor film is formed by causing crystal growth using a seed crystal with a hexagonal crystal structure including zinc as a nucleus, whereby a single crystal oxide semiconductor film or a substantially single crystal oxide semiconductor film is formed.

Method for manufacturing semiconductor device

A manufacturing method of a semiconductor device in which the threshold voltage is adjusted is provided. The semiconductor device includes a first semiconductor, an electrode electrically connected to the first semiconductor, a gate electrode, and an electron trap layer between the gate electrode and the first semiconductor. By performing heat treatment at higher than or equal to 125&#xb0; C. and lower than or equal to 450&#xb0; C. and, at the same time, keeping a potential of the gate electrode higher than a potential of the electrode for 1 second or more, the threshold voltage is increased.

A method for adjusting threshold of a semiconductor device is provided. In a plurality of semiconductor devices each including a semiconductor, a source or drain electrode electrically in contact with the semiconductor, a gate electrode, and a charge trap layer between a gate electrode and the semiconductor, a state where the potential of the gate electrode is set higher than the potential of the source or drain electrode while the semiconductor devices are heated at 150&#xb0; C. or higher and 300&#xb0; C. or lower is kept for one second or longer to trap electrons in the charge trap layer, so that the threshold is increased and Icut is reduced. Here, the potential difference between the gate electrode and the source or drain electrode is set so that it is different between the semiconductor devices, and the thresholds of the semiconductor devices are adjusted to be appropriate to each purpose.

Manufactured is a transistor including an oxide semiconductor layer, a source electrode layer and a drain electrode layer overlapping with part of the oxide semiconductor layer, a gate insulating layer overlapping with the oxide semiconductor layer, the source electrode layer, and the drain electrode layer, and a gate electrode overlapping with part of the oxide semiconductor layer with the gate insulating layer provided therebetween, wherein, after the oxide semiconductor layer which is to be a channel formation region is irradiated with light and the light irradiation is stopped, a relaxation time of carriers in photoresponse characteristics of the oxide semiconductor layer has at least two kinds of modes: &#x3c4;and &#x3c4;, &#x3c4;&#x3c;&#x3c4;is satisfied, and &#x3c4;is 300 seconds or less. In addition, a semiconductor device including the transistor is manufactured.

Transistor and semiconductor device

Semiconductor device and method for manufacturing semiconductor device including an electron trap layer

An oxide semiconductor layer in which 'safe' traps exist exhibits two kinds of modes in photoresponse characteristics. By using the oxide semiconductor layer, a transistor in which light deterioration is suppressed to the minimum and the electric characteristics are stable can be achieved. The oxide semiconductor layer exhibiting two kinds of modes in photoresponse characteristics has a photoelectric current value of 1 pA to 10 nA inclusive. When the average time &#x3c4;until which carriers are captured by the 'safe' traps is large enough, there are two kinds of modes in photoresponse characteristics, that is, a region where the current value falls rapidly and a region where the current value falls gradually, in the result of a change in photoelectric current over time.

Semiconductor device

A semiconductor device in which the threshold is adjusted is provided. In a transistor including a semiconductor, a source or drain electrode electrically connected to the semiconductor, a gate electrode, and an electron trap layer between the gate electrode and the semiconductor, the electron trap layer includes crystallized hafnium oxide. The crystallized hafnium oxide is deposited by a sputtering method using hafnium oxide as a target. When the substrate temperature is Tsub (&#xb0; C.) and the proportion of oxygen in an atmosphere is P (%) in the sputtering method, P&#x2267;45&#x2212;0.15&#xd7;Tsub is satisfied. The crystallized hafnium oxide has excellent electron trapping properties. By the trap of an appropriate number of electrons, the threshold of the semiconductor device can be adjusted.

Method for manufacturing semiconductor device comprising electron trap layer

A manufacturing method of a semiconductor device in which the threshold is corrected is provided. In a semiconductor device including a plurality of transistors each includes a semiconductor, a source or drain electrode electrically connected to the semiconductor, a gate electrode, and a charge trap layer between the gate electrode and the semiconductor, electrons are trapped in the charge trap layer by performing heat treatment and, simultaneously, keeping a potential of the gate electrode higher than that of the source or drain electrode for 1 second or more. By this process, the threshold increases and Icut decreases. A circuit for supplying a signal to the gate electrode and a circuit for supplying a signal to the source or drain electrode are electrically separated from each other. The process is performed in the state where the potential of the former circuit is set higher than the potential of the latter circuit.

A manufacturing method of a semiconductor device in which the threshold is adjusted is provided. In a semiconductor device including a plurality of transistors arranged in a matrix each including a semiconductor, a source or drain electrode electrically connected to the semiconductor, a gate electrode, and a charge trap layer between the gate electrode and the semiconductor, electrons are trapped in the charge trap layer by performing heat treatment and, simultaneously, keeping a potential of the gate electrode higher than that of the source or drain electrode for 1 second or more. By this process, the threshold increases and Icut decreases. A circuit that supplies a signal to the gate electrode (e.g., word line driver) is provided with a selection circuit formed of an OR gate, an XOR gate, or the like, whereby potentials of word lines can be simultaneously set higher than potentials of bit lines.

Semiconductor device and method for manufacturing semiconductor device for adjusting threshold thereof

An object is to provide a semiconductor device including an oxide semiconductor film, which has stable electrical characteristics and high reliability. A stack of first and second material films is formed by forming the first material film (a film having a hexagonal crystal structure) having a thickness of 1 nm to 10 nm over an insulating surface and forming the second material film having a hexagonal crystal structure (a crystalline oxide semiconductor film) using the first material film as a nucleus. As the first material film, a material film having a wurtzite crystal structure (e.g., gallium nitride or aluminum nitride) or a material film having a corundum crystal structure (&#x3b1;-AlO, &#x3b1;-GaO, InO, TiO, VO, CrO, or &#x3b1;-FeO) is used.

Semiconductor device and method for manufacturing the same

To provide a semiconductor device in which the threshold value is controlled. Furthermore, to provide a semiconductor device in which a deterioration in electrical characteristics which becomes more noticeable as a transistor is miniaturized can be suppressed. The semiconductor device includes a first semiconductor film, a source electrode and a drain electrode electrically connected to the first semiconductor film, a gate insulating film, and a gate electrode in contact with the gate insulating film. The gate insulating film includes a first insulating film and a trap film, and charge is trapped in a charge trap state in an interface between the first insulating film and the trap film or inside the trap film.

A method for manufacturing a semiconductor device with adjusted threshold is provided. In a semiconductor device including a semiconductor, a source or drain electrode electrically connected to the semiconductor, a first gate electrode and a second gate electrode between which the semiconductor is provided, a charge trap layer provided between the first gate electrode and the semiconductor, and a gate insulating layer provided between the second gate electrode and the semiconductor, a threshold is increased by trapping electrons in the charge trap layer by keeping a potential of the first gate electrode at a potential higher than a potential of the source or drain electrode for 1 second or more while heating. After the threshold adjustment process, the first gate electrode is removed or insulated from other circuits. Alternatively, a resistor may be provided between the first gate electrode and other circuits.

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Kanagawa, Japan

Takayuki Inoue