Showing papers by "Jun Koyama published in 2010"

Nonvolatile latch circuit and logic circuit, and semiconductor device using the same

Abstract: To provide a novel nonvolatile latch circuit and a semiconductor device using the nonvolatile latch circuit, a nonvolatile latch circuit includes a latch portion having a loop structure where an output of a first element is electrically connected to an input of a second element, and an output of the second element is electrically connected to an input of the first element; and a data holding portion for holding data of the latch portion. In the data holding portion, a transistor using an oxide semiconductor as a semiconductor material for forming a channel formation region is used as a switching element. In addition, an inverter electrically connected to a source electrode or a drain electrode of the transistor is included. With the transistor, data held in the latch portion can be written into a gate capacitor of the inverter or a capacitor which is separately provided.

Logic circuit and semiconductor device

Abstract: To reduce a leakage current of a transistor so that malfunction of a logic circuit can be suppressed. The logic circuit includes a transistor which includes an oxide semiconductor layer having a function of a channel formation layer and in which an off current is 1×10−13 A or less per micrometer in channel width. A first signal, a second signal, and a third signal that is a clock signal are input as input signals. A fourth signal and a fifth signal whose voltage states are set in accordance with the first to third signals which have been input are output as output signals.

43.4: Low Power LC Display Using In-Ga-Zn-Oxide TFTs Based on Variable Frame Frequency

Abstract: By using an oxide semiconductor, we successfully prototyped a 3.4-inch QHD LCD panel including data and scan drivers; their power consumption is reduced by variable frame frequency (from 1/60 fps to 120 fps) depending on images. Low frame frequency in displaying still images on a PC monitor can reduce eyestrain.

Method for driving liquid crystal display device

Abstract: The liquid crystal display device includes a first substrate provided with a terminal portion, a switching transistor, a driver circuit portion, and a pixel circuit portion including a pixel transistor and a plurality of pixels, a second substrate provided with a common electrode electrically connected to the terminal portion through the switching transistor, and liquid crystal between a pixel electrode and the common electrode. In a period during which a still image is switched to a moving image, the following steps are sequentially performed: a first step of supplying the common potential to the common electrode; a second step of supplying a power supply voltage to the driver circuit portion; a third step of supplying a clock signal to the driver circuit portion; and a fourth step of supplying a start pulse signal to the driver circuit portion.

Liquid crystal display device and electronic device including the liquid crystal display device

Abstract: In a liquid crystal display device including a plurality of pixels in a display portion and configured to performed display in a plurality of frame periods, each of the frame periods includes a writing period and a holding period, and after an image signal is input to each of the plurality of pixels in the writing period, a transistor included in each of the plurality of pixels is turned off and the image signal is held for at least 30 seconds in the holding period. The pixel includes a semiconductor layer including an oxide semiconductor layer, and the oxide semiconductor layer has a carrier concentration of less than 1×1014/cm3.

Semiconductor Device and Method for Fabricating the Same

Abstract: The invention primarily provides gate electrodes and gate wirings permitting large-sized screens for active matrix-type display devices, wherein, in order to achieve this object, the construction of the invention is a semiconductor device having, on the same substrate, a pixel TFT provided in a display region and a driver circuit TFT provided around the display region, wherein the gate electrodes of the pixel TFT and the driver circuit TFT are formed from a first conductive layer, the gate electrodes are in electrical contact through connectors with gate wirings formed from a second conductive layer, and the connectors are provided outside the channel-forming regions of the pixel TFT and the driver circuit TFT.

Voltage regulator circuit

Abstract: A voltage regulator circuit includes a transistor and a capacitor. The transistor includes a gate, a source, and a drain, a first signal is inputted to one of the source and the drain, a second signal which is a clock signal is inputted to the gate, an oxide semiconductor layer is used for a channel formation layer, and an off-state current is less than or equal to 10 aA/μm. The capacitor includes a first electrode and a second electrode, the first electrode is electrically connected to the other of the source and the drain of the transistor, and a high power source voltage and a low power source voltage are alternately applied to the second electrode.

Liquid crystal display device and electronic apparatus having the same

Abstract: A liquid crystal display device includes: a driver circuit portion; a pixel portion; a signal generation circuit for generating a control signal for driving the driver circuit portion and an image signal which is supplied to the pixel portion; a memory circuit; a comparison circuit for detecting a difference of image signals for a series of frame periods among image signals stored for respective frame periods in the memory circuit; a selection circuit which selects and outputs the image signals for the series of frame periods when the difference is detected in the comparison circuit; and a display control circuit which supplies the control signal and the image signals output from the selection circuit, to the driver circuit portion when the difference is detected in the comparison circuit, and stops supplying the control signal to the driver circuit portion when the difference is not detected in the comparison circuit.

Display device and electronic device including display device

Abstract: Objects are to provide a display device the power consumption of which is reduced, to provide a self-luminous display device the power consumption of which is reduced and which is capable of long-term use in a dark place. A circuit is formed using a thin film transistor in which a highly-purified oxide semiconductor is used and a pixel can keep a certain state (a state in which a video signal has been written). As a result, even in the case of displaying a still image, stable operation is easily performed. In addition, an operation interval of a driver circuit can be extended, which results in a reduction in power consumption of a display device. Moreover, a light-storing material is used in a pixel portion of a self-luminous display device to store light, whereby the display device can be used in a dark place for a long time.

Analog circuit and semiconductor device

Abstract: An object is to obtain a semiconductor device having a high sensitivity in detecting signals and a wide dynamic range, using a thin film transistor in which an oxide semiconductor layer is used. An analog circuit is formed with the use of a thin film transistor including an oxide semiconductor which has a function as a channel formation layer, has a hydrogen concentration of 5×10 19 atoms/cm 3 or lower, and substantially functions as an insulator in the state where no electric field is generated. Thus, a semiconductor device having a high sensitivity in detecting signals and a wide dynamic range can be obtained.

Driver circuit, display device including the driver circuit, and electronic appliance including the display device

Abstract: An object of the present invention is to provide a driver circuit including a normally-on thin film transistor, which driver circuit ensures a small malfunction and highly reliable operation. The driver circuit includes a static shift register including an inverter circuit having a first transistor and a second transistor, and a switch including a third transistor. The first to third transistors each include a semiconductor layer of an oxide semiconductor and are depletion-mode transistors. An amplitude voltage of clock signals for driving the third transistor is higher than a power supply voltage for driving the inverter circuit.

Development of Liquid Crystal Display Panel Integrated with Drivers Using Amorphous In–Ga–Zn-Oxide Thin Film Transistors

Abstract: We designed, prototyped, and evaluated a liquid crystal panel integrated with a gate driver and a source driver using amorphous In–Ga–Zn-oxide thin film transistors (TFTs). Using bottom-gate bottom-contact (BGBC) thin film transistors, superior characteristics could be obtained. We obtained TFT characteristics with little variation even when the thickness of the gate insulator (GI) film was reduced owing to etching of source/drain (S/D) wiring, which is a typical process for the BGBC TFT. Moreover, a favorable ON-state current was obtained even when an In–Ga–Zn-oxide layer was formed over the S/D electrode. Since the upper portion of the In–Ga–Zn-oxide layer is not etched, the BGBC structure is predicted to be effective in thinning the In–Ga–Zn-oxide layer in the future. Upon evaluation, we found that the prototyped liquid crystal panel integrated with the gate and source drivers using the TFTs with improved characteristics had stable drive.

Semiconductor device comprising oxide semiconductor layer

Abstract: It is an object to provide a semiconductor device typified by a display device having a favorable display quality, in which parasitic resistance generated in a connection portion between a semiconductor layer and an electrode is suppressed and an adverse effect such as voltage drop, a defect in signal wiring to a pixel, a defect in grayscale, and the like due to wiring resistance are prevented. In order to achieve the above object, a semiconductor device according to the present invention may have a structure where a wiring with low resistance is connected to a thin film transistor in which a source electrode and a drain electrode that include metal with high oxygen affinity are connected to an oxide semiconductor layer with a suppressed impurity concentration. In addition, the thin film transistor including the oxide semiconductor may be surrounded by insulating films to be sealed.

18.3: Low Power 3.4inch Quarter High Definition OLED Display Using InGaZnOxide TFTs and White Tandem OLED

Abstract: We recently succeeded in manufacturing a 34 inch QHD OLED display 326ppi with high aperture ratio, 40%, in which we adopted the white OLED using a tandem structure and a color filter method Besides, we achieved 40% lower the power consumption of the driver circuit 60mW by improving it

Oxide-based thin-film transistor (TFT) semiconductor memory device having source/drain electrode of one transistor connected to gate electrode of the other

Abstract: It is an object to provide a semiconductor having a novel structure. In the semiconductor device, a plurality of memory elements are connected in series and each of the plurality of memory elements includes first to third transistors thus forming a memory circuit. A source or a drain of a first transistor which includes an oxide semiconductor layer is in electrical contact with a gate of one of a second and a third transistor. The extremely low off current of a first transistor containing the oxide semiconductor layer allows storing, for long periods of time, electrical charges in the gate electrode of one of the second and the third transistor, whereby a substantially permanent memory effect can be obtained. The second and the third transistors which do not contain an oxide semiconductor layer allow high-speed operations when using the memory circuit.

76.1: High Aperture Ratio LCD Display using In-Ga-Zn-Oxide TFTs without Storage Capacitor

Abstract: By using oxide semiconductors, we succeeded in prototyping a 3.4-inch QHD LCD panel whose aperture ratio is high and pixels do not include a storage capacitor. The aperture ratio is increased from 40 % to 59%, resulting in reduction of power consumption in a backlight unit.

Semiconductor device having an oxide semiconductor with a crystalline region and manufacturing method thereof

Abstract: An object of an embodiment of the present invention is to manufacture a semiconductor device with high display quality and high reliability, which includes a pixel portion and a driver circuit portion capable of high-speed operation over one substrate, using transistors having favorable electric characteristics and high reliability as switching elements. Two kinds of transistors, in each of which an oxide semiconductor layer including a crystalline region on one surface side is used as an active layer, are formed in a driver circuit portion and a pixel portion. Electric characteristics of the transistors can be selected by choosing the position of the gate electrode layer which determines the position of the channel. Thus, a semiconductor device including a driver circuit portion capable of high-speed operation and a pixel portion over one substrate can be manufactured.

P‐143: Possibility of Reflective LC Display Using Oxide Semiconductor TFTs as Electronic Paper Display

Abstract: We successfully prototyped a 3.4-inch QHD PDLCD panel integrally including data and scan drivers of oxide semiconductor TFTs and capable of displaying still images at 0.2 fps, which can be adopted to electronic paper displays. This panel can display both still images and moving images and reduce power consumption.

Device including nonvolatile memory element

Abstract: A device including a novel nonvolatile memory element is provided. A device including a nonvolatile memory element in which an oxide semiconductor is used as a semiconductor material for a channel formation region. The nonvolatile memory element includes a control gate, a charge accumulation layer which overlaps with the control gate with a first insulating film provided therebetween, and an oxide semiconductor layer formed using an oxide semiconductor material, which overlaps with the charge accumulation layer with a second insulating film provided therebetween.

Liquid crystal display device viewable in dim ambient light

Abstract: An object is to provide a liquid crystal display device in which image display can be recognized even in an environment where light is dim around the liquid crystal display device. Another object is to provide a liquid crystal display device capable of image display in both modes of a reflective mode in which external light is used as a light source and a transmissive mode in which a backlight is used. One pixel is provided with a pixel electrode having both of a region where light incident through a liquid crystal layer is reflected and a region having a light-transmitting property, so that image display can be performed in both modes of a reflective mode in which external light is used as a light source and a transmissive mode in which a backlight is used.

Semiconductor storage device with integrated capacitor and having transistor overlapping sections

Abstract: To provide a storage device in which advantages of both a nonvolatile storage device and a volatile storage device can be obtained, a semiconductor device includes a first transistor provided in or over a substrate and a second transistor provided above the first transistor, where at least part of the first transistor and the second transistor are overlapped with each other, and a gate electrode of the first transistor and a source or drain electrode of the second transistor are electrically connected to each other. It is preferable that the first transistor be provided using single crystal silicon and the second transistor be provided using an oxide semiconductor having extremely low off-state current.

Driver‐circuits‐integrated LCDs based on novel amorphous In‐Ga‐Zn‐oxide TFT

Abstract: — A liquid-crystal panel integrated with a gate driver and a source driver by using amorphous In—Ga—Zn-oxide TFTs was designed, prototyped, and evaluated. By using the process of bottom-gate bottom-contact (BGBC) TFTs, amorphous In—Ga—Zn-oxide TFTs with superior characteristics were provided. Further, for the first time in the world, a 4-in. QVGA liquid-crystal panel integrated with a gate driver and a source driver was developed by using BGBC TFTs formed from an oxide semiconductor. By evaluating the liquid-crystal panel, its functionality was successfully demonstrate. Based on the findings, it is believed that the novel BGBC amorphous In—Ga—Zn-oxide TFT will be a promising candidate for future large-screen backplanes having high definition.

7.3: Development of 3.4-in. QHD LCD Having Blue-Phase LC and Oxide-Semiconductor TFTs

Abstract: We fabricated a liquid crystal panel by combining a blue phase material having short response time with an TFT formed using an oxide semiconductor having high mobility and stable normallyoff characteristics. It was very effective to use a highdefinition InGaZnOxide TFT substrate that we had developed.

Semiconductor memory device including semiconductor and oxide semiconductor transistors

Abstract: It is an object to provide a semiconductor device with a novel structure. The semiconductor device includes memory cells connected to each other in series and a capacitor. One of the memory cells includes a first transistor connected to a bit line and a source line, a second transistor connected to a signal line and a word line, and a capacitor connected to the word line. The second transistor includes an oxide semiconductor layer. A gate electrode of the first transistor, one of a source electrode and a drain electrode of the second transistor, and one electrode of the capacitor are connected to one another.

Dispositif à semi-conducteur

Abstract: L'invention concerne un dispositif a semi-conducteur comprenant une etiquette d'identification par radiofrequence (RFID) qui peut transmettre et recevoir des informations individuelles sans avoir besoin de changer de pile a cause de la decharge au fil du temps de ladite pile servant a l'alimenter et qui peut etre alimente pour qu'il soit en etat de transmettre et de recevoir les informations individuelles meme quand une onde electromagnetique externe est insuffisante. Le dispositif semi-conducteur comprend un circuit de traitement du signal, un premier circuit d'antenne et un second circuit d'antenne relies de maniere fonctionnelle au circuit de traitement du signal et une pile reliee de maniere fonctionnelle au circuit de traitement du signal. Le premier circuit d'antenne transmet et recoit un signal pour transmettre des donnees enregistrees dans le circuit de traitement du signal; le second circuit d'antenne recoit un signal pour recharger la pile; et un signal recu par le premier circuit d'antenne et un signal recu par le second circuit d'antenne ont des longueurs d'onde differentes.