Abstract: In a matrix including a plurality of memory cells, each in which a drain of a writing transistor is connected to a gate of a reading transistor and the drain is connected to one electrode of a capacitor, a gate of the writing transistor is connected to a writing word line, a source of the writing transistor and a source of the reading transistor is connected to a bit line, and a drain of the reading transistor is connected to a reading word line. A conductivity type of the writing transistor is different from a conductivity type of the reading transistor. In order to increase the integration degree, a bias line may be substituted with a reading word line in another row, or memory cells are connected in series so as to have a NAND structure, and a reading word line and a writing word line may be shared.

Abstract: An object is to provide a memory device for which a complex manufacturing process is not necessary and whose power consumption can be suppressed, and a signal processing circuit including the memory device. In a memory element including a phase-inversion element such as an inverter or a clocked inverter, a capacitor which holds data and a switching element which controls storing and releasing of electric charge in the capacitor are provided. For the above switching element, a transistor including amorphous silicon, polysilicon, microcrystalline silicon, or a compound semiconductor such as an oxide semiconductor in a channel formation region is used. The channel length of the transistor is ten times or more as large as the minimum feature size or greater than or equal to 1 ?m. The above memory element is used for a memory device such as a register or a cache memory in the signal processing circuit.

Abstract: To optimize the arrangement of configuration data stored in a configuration memory. A lookup table includes a memory configured to store configuration data, a plurality of multiplexers each configured to select one signal from a plurality of input signals in accordance with the configuration data supplied from the memory and output the one signal, and an inverter. The plurality of multiplexers are connected in a binary tree with multiple levels. The inverter is provided between one of input terminals of a multiplexer in an uppermost level and an output terminal of a multiplexer in one level lower than the uppermost level. Signal selection is performed in each of the multiplexers so that the multiplexer in the uppermost level outputs, as an output signal, one signal of all input signals of the multiplexers in a lowermost level.

Abstract: A level shifter converting a binary signal having a first potential and a second potential into a signal having the first potential and a third potential, and a signal processing circuit using the level shifter are provided. The first potential is higher than the second potential. The second potential is higher than the third potential. The potential difference between the first potential and the third potential may be more than or equal to 3 V and less than 4 V. The level shifter includes a current control circuit which generates a second signal for operating an amplifier circuit for a certain period in accordance with the potential change of the first signal which is input to the amplifier circuit. The output of level shifter is input to a gate of an N-channel transistor whose threshold voltage is lower than 0 V.

Abstract: In a conventional DRAM, a decrease in the capacitance of a capacitor causes an error in reading data. A plurality of memory blocks MB is connected to one bit line BL_m. Each memory block MB includes a sub bit line SBL, a plurality of memory cells, and a precharge transistor. The drain of a transistor of the memory cell is connected one of the bit line BL_m and the sub bit line SBL, whereas a capacitor of the memory cell is connected to the other one of the bit line BL_m and the sub bit line SBL. The capacitance of the sub bit line SBL is sufficiently low; thus, a potential change due to electric charges of the capacitor of the memory cell can be amplified by an amplifier circuit AMP without an error and the amplified signal can be output to the bit line.

Abstract: A signal processing device is produced. The signal processing device including a first transistor with high off-state resistance, a second transistor which controls conduction between two different nodes, a capacitor which holds electric charge, and a current control element such as a transistor or a resistor. The first node to which a gate of the second transistor and a second electrode of the current control element are connected, and the second node to which one of a source and a drain of the first transistor, a first electrode of the capacitor, and a first electrode of the current control element are connected. The capacitance (including a parasitic capacitance) of the second node is greater than ten times the capacitance (including a parasitic capacitance) of the first node. The capacitance does not affect the first node; thus, a boosting effect is large and charge retention characteristics are favorable.

Abstract: A programming element including a first transistor, a second transistor, and a capacitor between a logic circuit using a semiconductor element and a power supply is provided. In the programming element, a node where a drain electrode of the first transistor, a gate electrode of the second transistor, and one of electrodes of the capacitor are electrically connected to each other is formed. A potential can be supplied to each of a source electrode of the first transistor and the other of the electrodes of the capacitor. The power supply and the logic circuit are electrically connected to each other through a source electrode and a drain electrode of the second transistor. A connection state between the power supply and the logic circuit is controlled in accordance with the state of the second transistor.

Abstract: To optimize the arrangement of configuration data stored in a configuration memory. A lookup table includes a memory configured to store configuration data, a plurality of multiplexers each configured to select one signal from a plurality of input signals in accordance with the configuration data supplied from the memory and output the one signal, and an inverter. The plurality of multiplexers are connected in a binary tree with multiple levels. The inverter is provided between one of input terminals of a multiplexer in an uppermost level and an output terminal of a multiplexer in one level lower than the uppermost level. Signal selection is performed in each of the multiplexers so that the multiplexer in the uppermost level outputs, as an output signal, one signal of all input signals of the multiplexers in a lowermost level.

Abstract: A method of reducing power consumption of an electro-optical display device which can display a still image with the use of analog signals. A circuit in which a small amount of leakage current flows between a source and a drain of a selection transistor when the selection transistor is off; the source of the selection transistor is connected to a gate of an N-channel driving transistor, a gate of a P-channel driving transistor, and one electrode of a capacitor; and a source of each of the N-channel driving transistor and the P-channel driving transistor is connected to one electrode of a display element is provided in each pixel. The longest time of one frame is set to 100 seconds or longer with the use of such a circuit, whereby power consumption at the time of rewriting is reduced.

Abstract: A highly integrated gain cell-type semiconductor memory is provided. A first insulator, a read bit line, a second insulator, a third insulator, a first semiconductor film, first conductive layers, and the like are formed. A projecting insulator is formed thereover. Then, second semiconductor films and a second gate insulating film are formed to cover the projecting insulator. After that, a conductive film is formed and subjected to anisotropic etching, so that write word lines are formed on side surfaces of the projecting insulator. A third contact plug for connection to a write bit line is formed over a top of the projecting insulator. With such a structure, the area of the memory cell can be 4F2 at a minimum.

Abstract: A semiconductor memory device in which capacitance of a capacitor is lower and integration degree is higher. A plurality of memory blocks is connected to one bit line BL_m. A memory block MB_n_m includes a sub bit line SBL_n_m, a write switch, and a plurality of memory cells. A sub bit line SBL_n+1_m adjacent to the sub bit line SBL_n_m is connected to an amplifier circuit AMP_n/n+1_m including two inverters and two selection switches. A circuit configuration of the amplifier circuit can be changed with the selection switches. The amplifier circuit is connected to the bit line BL_m through a read switch. Because of a sufficiently low capacitance of the sub bit line SBL_n_m, potential change due to electric charges of the capacitor in each memory cell can be amplified by the amplifier circuit AMP_n/n+1_m without an error, and the amplified data can be output to the bit line BL_m.

Abstract: An object is to increase the retention characteristics of a memory device formed using a wide bandgap semiconductor. A bit line controlling transistor is inserted in a bit line in series. The minimum potential of a gate of the transistor is set to a sufficiently negative value. The gate of the transistor is connected to a bit line controlling circuit connected to a battery. The minimum potential of the bit line is set higher than that of a word line. When power from an external power supply is interrupted, the bit line is cut off by the transistor, ensuring prevention of outflow of charge in the bit line. The potential of a source or a drain (bit line) of a cell transistor is sufficiently higher than that of a gate of the cell transistor, resulting in an absolute off-state; thus, data can be retained. Other embodiments are disclosed.

Abstract: A programming element including a first transistor, a second transistor, and a capacitor between a logic circuit using a semiconductor element and a power supply is provided. In the programming element, a node where a drain electrode of the first transistor, a gate electrode of the second transistor, and one of electrodes of the capacitor are electrically connected to each other is formed. A potential can be supplied to each of a source electrode of the first transistor and the other of the electrodes of the capacitor. The power supply and the logic circuit are electrically connected to each other through a source electrode and a drain electrode of the second transistor. A connection state between the power supply and the logic circuit is controlled in accordance with the state of the second transistor.

Abstract: It is an object to reduce power consumption of a 2Tr1C type semiconductor memory device. The absolute value of the threshold voltage of a reading transistor is made larger than a fluctuation range of a data potential of a bit line (or the fluctuation range of the data potential of the bit line is made smaller than the absolute value of the threshold voltage of the reading transistor), whereby the potential of a source line can be fixed, a fluctuation in a potential of a writing word line can be made smaller, and a potential of a reading word line is fluctuated only at the time of reading. Further, a gate of such a transistor the absolute value of the threshold voltage of which is large is formed using a material having a high work function, such as indium nitride.

Abstract: To provide a power MISFET using oxide semiconductor. A gate electrode, a source electrode, and a drain electrode are formed so as to interpose a semiconductor layer therebetween, and a region of the semiconductor layer where the gate electrode and the drain electrode do not overlap with each other is provided between the gate electrode and the drain electrode. The length of the region is from 0.5 ?m to 5 ?m. In such a power MISFET, a power source of 100 V or higher and a load are connected in series between the drain electrode and the source electrode, and a control signal is input to the gate electrode.

Abstract: A novel semiconductor memory device whose power consumption is low is provided. A source of a writing transistor WTr_n_m, a gate of a reading transistor RTr_n_m, and one electrode of a capacitor CS_n_m are connected to each other. A gate and a drain of the writing transistor WTr_n_m are connected to a writing word line WWL_n and a writing bit line WBL_m, respectively. The other electrode of the capacitor CS_n_m is connected to a reading word line RWL_n. A drain of the reading transistor RTr_n_m is connected to a reading bit line RBL_m. Here, the potential of the reading bit line RBL_m is input to an inverting amplifier circuit such as a flip-flop circuit FF_m to be inverted by the inverting amplifier circuit. This inverted potential is output to the writing bit line WBL_m.

Abstract: In a memory element including a pair of inverters, a capacitor which holds data, and a switching element which controls accumulating and releasing of electric charge of the capacitor are provided. For example, one electrode of the capacitor is connected to a first node, which is an input or output terminal of one of the pair of inverters, and the other electrode of the capacitor is connected to one electrode the switching element. The other electrode of the switching element is connected to a second node, which is the output or input terminal of the one of the pair of inverters. With such a connection structure, the absolute value of the potential difference between the first node and the second node at the time of data restoring can be large enough, whereby errors at the time of data restoring can be reduced.

Abstract: 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.

Abstract: Provided is a novel structure of a field effect transistor using a metal-semiconductor junction. The field effect transistor includes a wiring which is provided over a substrate and also functions as a gate electrode; an insulating film which is provided over the wiring, has substantially the same shape as the wiring, and also functions as a gate insulating film; a semiconductor layer which is provided over the insulating film and includes an oxide semiconductor and the like; an oxide insulating layer which is provided over the semiconductor layer and whose thickness is 5 times or more as large as the sum of the thickness of the insulating film and the thickness of the semiconductor layer or 100 nm or more; and wirings which are connected to the semiconductor layer through openings provided in the oxide insulating layer.

Abstract: To optimize the arrangement of configuration data stored in a configuration memory. A lookup table includes a memory configured to store configuration data, a plurality of multiplexers each configured to select one signal from a plurality of input signals in accordance with the configuration data supplied from the memory and output the one signal, and an inverter. The plurality of multiplexers are connected in a binary tree with multiple levels. The inverter is provided between one of input terminals of a multiplexer in an uppermost level and an output terminal of a multiplexer in one level lower than the uppermost level. Signal selection is performed in each of the multiplexers so that the multiplexer in the uppermost level outputs, as an output signal, one signal of all input signals of the multiplexers in a lowermost level.