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 plurality of memory cells included in a memory cell array are divided into a plurality of blocks every plural rows. A common bit line is electrically connected to the divided bit lines through selection transistors in the blocks. One of the memory cells includes a first transistor, a second transistor, and a capacitor. The first transistor includes a first channel formation region. The second transistor includes a second channel formation region. The first channel formation region includes a semiconductor material different from the semiconductor material of the second channel formation region.

Abstract: A semiconductor device is disclosed in which a signal line and a drive circuit driving the signal line in response to a signal to be transmitted are provided. A transistor of a floating body type is further provided that includes a gate, a source, a drain, and a body between the source and drain which is brought into an electrically floating state. The gate is connected to the signal line, and at least one of the source and drain is connected to a control node that is supplied with a control signal. The control signal is configured to receive a control signal that changes from the first level to a second level during the period of time when the drive circuit is driving the signal node.

Abstract: A memory mat (101) includes a main body portion (200) that includes a first capacitor (203A), a linear conductive film (204) that is formed between the main body portion (200) and a peripheral circuit (104), and a second capacitor (203B) that is formed to be in contact with the conductive film (204) at a bottom of the second capacitor (203B). The first capacitor (203A) is in contact with a contact layer (202) at a bottom of the first capacitor (203A).

Abstract: A method of operating a memory circuit compatible with dynamic random access memories (DRAM) and static random access memories (SRAM) is disclosed. The method includes selecting a word line (708) connected to a row of memory cells in response to a plurality of row address signals and selecting a plurality of columns (706,710) of memory cells in response to a plurality of column address signals. A first part (714) of the plurality of columns is selected in response to a first voltage applied to the selected word line. A second part (716) of the plurality of columns is selected in response to a second voltage applied to the selected word line.

Abstract: A low-power programmable LSI that can perform dynamic configuration is provided. The programmable LSI includes a plurality of logic elements. The plurality of logic elements each include a configuration memory. Each of the plurality of logic elements performs different arithmetic processing and changes an electrical connection between the logic elements, in accordance with the configuration data stored in the configuration memory. The configuration memory includes a set of a volatile storage circuit and a nonvolatile storage circuit. The nonvolatile storage circuit includes a transistor whose channel is formed in an oxide semiconductor layer and a capacitor whose one of a pair of electrodes is electrically connected to a node that is set in a floating state when the transistor is turned off.

Abstract: A semiconductor device includes a first pad, and a sub-trunk line elongated in a first direction; a main-trunk line arranged between the first pad and the sub-trunk line and elongated in the first direction. The semiconductor device further includes a first plug line elongated in a second direction crossing the first direction, the first plug line being connected between the first pad and the main-trunk line without being direct contact with the sub-trunk line. The semiconductor device further includes a second plug line elongated in the second direction, the second plug line being connected between the main-trunk line and the sub-trunk line, and a first element coupled to the sub-trunk line.

Abstract: A clock generator circuit generates a sequence of clock signals equally phased from each other from a master clock signal. The clock generator is formed by inner and outer delay-locked loops. The inner delay-locked loop includes a voltage controlled delay line that delays a reference clock applied to its input by a plurality of respective delays. Two of the clock signals in the sequence are applied to a phase detector so that the signals at the outputs of the delay line have predetermined phases relative to each other. The outer delay-locked loop is formed by a voltage controlled delay circuit that delays the command clock by a voltage controlled delay to provide the reference clock to the delay line of the inner delay-locked loop. The outer delay-locked loop also includes a phase detector that compares the command clock to one of the clock signals in the sequence generated by the delay line. The outer delay-locked loop thus locks one of the clock signals in the sequence to the command clock.

Abstract: Integrated circuits may communicate with off-chip memory. Such types of integrated circuits may include memory interface circuitry that is used to interface with the off-chip memory. The memory interface circuitry may be calibrated using a procedure that includes read calibration, write leveling, read latency tuning, and write calibration. Read calibration may serve to ensure proper gating of data strobe signals and to center the data strobe signals with respect to read data signals. Write leveling ensures that the data strobe signals are aligned to system clock signals. Read latency tuning serves to adjust read latency to ensure optimum read performance. Write calibration may serve to center the data strobe signals with respect to write data signals. These calibration operations may be used to calibrate memory systems supporting a variety of memory communications protocols.

Abstract: A memory cell comprising a ferroelectric capacitor, a variable impedance element and a conductive load is disclosed. The ferroelectric capacitor, characterized by first and second polarization states, is connected between a control terminal and a first switch terminal. The variable impedance element has an impedance between the first and second switch terminals that is determined by a signal on a control terminal. The conductive load is connected between a first power terminal and the first switch terminal. The second switch terminal is connected to a second power terminal. When a potential difference is applied between the first and second power terminals, a potential on the first switch terminal varies in a manner determined by the state of polarization of the ferroelectric capacitor.

Abstract: The memory circuit has a first writing mode in which data can be retained for a long time and a second writing mode in which data can be written at high speed. The memory circuit in which data reading is performed on the basis of a determined conductive state of a transistor includes first and second capacitor parts that are connected through a switch and retain electric charge corresponding to the data. The first writing mode is a mode where the switch is on and electric charge corresponding to the data is accumulated in the first and second capacitor parts that are electrically connected. The second writing mode is a mode where the switch is off, electric charge corresponding to the data is accumulated in the first capacitor part, and electric charge corresponding to the data is not accumulated in the second capacitor part.

Abstract: A system for charging a low voltage power domain in a low power DRAM includes: a first capacitor, for providing a local domain power voltage supply; a first transistor, coupled to the first capacitor and a voltage supply and turned on by a powerdown signal, the first transistor for decoupling the first capacitor during powerdown mode, and charging the capacitor to provide the local domain power voltage supply when exiting powerdown mode; a second capacitor selectively coupled to the voltage supply or the local domain voltage power supply; and a second transistor, coupled to the second capacitor, the powerdown signal, and the local domain power voltage supply, for decoupling the second capacitor from the local domain power voltage supply during powerdown mode and coupling the second capacitor to the local domain power voltage supply when exiting powerdown mode.

Abstract: The semiconductor device includes a first wiring; a second wiring; a third wiring; a fourth wiring; a first transistor having a first gate electrode, a first source electrode, and a first drain electrode; and a second transistor having a second gate electrode, a second source electrode, and a second drain electrode. The first transistor is formed on or in a substrate including a semiconductor material. The second transistor includes an oxide semiconductor layer.

Abstract: According to one embodiment, a nonvolatile semiconductor memory device includes a plurality of first interconnections arranged parallel, a plurality of second interconnections arranged parallel to intersect the first interconnections, and memory cell portions respectively arranged at intersecting portions between the first and second interconnections and each configured by laminating a variable-resistance element and a diode element. The diode element has a laminated structure having a first insulating film, a conductive fine grain layer and a second insulating film. The physical film thickness of the second insulating film is greater than the first insulating film and the dielectric constant of the second insulating film is greater than the first insulating film.

Abstract: A memory includes first and second select gate transistors, memory cells, a source line, a bit line, a selected word line which is connected to a selected memory cell as a target of a verify reading, a non-selected word line which is connected to a non-selected memory cell except the selected memory cell, a potential generating circuit for generating a selected read potential which is supplied to the selected word line, and generating a non-selected read potential larger than the selected read potential, which is supplied to the non-selected word line, and a control circuit which classifies a threshold voltage of the selected memory cell to one of three groups by verifying which area among three area which are isolated by two values does a cell current of the selected memory cell belong, when the selected read potential is a first value.

Abstract: A memory system includes a plurality of memory cells. Each memory cell includes a first storage cell including a first capacitor configured to store a first analog charge representing a first Boolean value, a second storage cell including a second capacitor configured to store a second analog charge representing a second Boolean value, and a charging path configured to apply, for a first time duration, a voltage to the first capacitor or the second capacitor during a write operation. Each memory cell includes a voltage comparator configured to output a Boolean value based upon a comparison of the first analog charge and the second analog charge during a read operation.

Abstract: A dynamic random access memory (DRAM) device has an array of DRAM cells of rows by columns. Each DRAM cell of the array is coupled with a wordline of a corresponding row and a bitline of a corresponding column. Entry into and an exit from the self-refresh mode is detected by a mode detector and a self-refresh mode signal is provided. An oscillation circuit generates in response to the self-refresh mode signal a basic time period. A first frequency divider/time period multiplier changes the basic time period in accordance with a process variation factor relating to the DRAM device. A second frequency divider/time period multiplier further changes the changed time period in accordance with a temperature change factor. In the self-refresh mode, data stored in the DRAM cells is refreshed. In accordance with the two factors, the DRAM devices perform and achieve reliable self-refresh for variable DRAM cell retention time.

Abstract: A method includes forming an ESD diode including performing an epitaxy growth to form an epitaxy region comprising silicon and substantially free from germanium. The epitaxy region is doped with a p-type impurity to form a p-type region, wherein the p-type region forms an anode of the ESD diode.

Abstract: In a conventional DRAM, errors in reading data are likely to occur when the capacitance of a capacitor is reduced. A plurality of cells is connected to one main bit line Each cell includes a sub bit line and 2 to 32 memory cells. Further, each cell includes a selection transistor and a reading transistor, and a sub bit line is connected to a gate of the reading transistor. Since the parasitic capacitance of the sub bit line is sufficiently small, data of electric charge of a capacitor of each memory cell can be amplified without an error in the reading transistor and output to the main bit line.

Abstract: A semiconductor memory device includes a memory cell and a first reference memory cell. The memory cell includes a first switching element and a first capacitor for storing data. The first switching element is controlled by a first wordline, and has a first terminal connected to a first terminal of the first capacitor and a second terminal connected to a first bitline. The first capacitor has a second terminal for receiving a first plate voltage. The first reference memory cell includes a first reference switching element and a first capacitor. The first switching element is controlled by a first reference wordline, and has a first terminal connected to a first terminal of the first reference capacitor and a second terminal connected to a second bitline. The first reference capacitor has a second terminal receiving a first reference plate voltage different from the first plate voltage.

Abstract: An embodiment is directed to an integrated circuit device having programmable input capacitance. For example, a programmable register of a memory device may store a value representative of an adjustment to the input capacitance value of a control pin. An embodiment is directed to controlling the skew of a synchronous memory system by allowing programmability of the lighter loaded pins in order to increase their load to match the more heavily loaded pins. By matching lighter loaded pins to more heavily loaded pins, the system exhibits improved synchronization of propagation delays of the control and address pins. In addition, an embodiment provides the ability to vary the loading depending on how many ranks are on the device.

Abstract: A memory device, system and fabrication method relating to a vertical memory cell including a semiconducting pillar extending outwardly from an integrally connected semiconductor substrate are disclosed. A first source/drain region is fowled in the substrate and a body region and a second source/drain region are formed within the pillar. A first gate is coupled to a first side of the pillar for coupling the first and second source/drain regions together when activated. The vertical memory cell also includes a storage capacitor formed on an extended end of the semiconducting pillar and electrically coupled to the second source/drain region.

Abstract: A dynamic random access memory (DRAM) includes a substrate, a plurality of bit lines, a plurality of word lines, a plurality of recess channels, a plurality of conductive plugs and a plurality of trench capacitors. In the DRAM, the bit lines are disposed on the substrate in a first direction, and the word lines are disposed on the bit lines in a second direction. Each recess channel is in the substrate between two bit lines below the word line, and each conductive plug connects each recess channel and the word lines. Each trench capacitor is disposed in the substrate between two bit lines where the recess channels are not formed. Because the word lines can be electrically connected with the recess channels directly without using an additional chip area, the WL access time can be accelerated without an increase of the chip size.

Abstract: Methods, devices, and systems are disclosed for a memory cell having a floating body. A memory cell may include a transistor over an insulation layer, the transistor including a source, and a drain. The memory cell may also include a floating body including a first region positioned between the source and the drain, a second region positioned remote from each of the source and drain, and a passage extending through the insulation layer and coupling the first region to the second region. Additionally, the memory cell may include a bias gate at least partially surrounding the second region and configured for operably coupling to a bias voltage. Furthermore, the memory cell may include a plurality of dielectric layers, wherein each outer vertical surface of the second region has a dielectric layer of the plurality adjacent thereto.

Abstract: A method for performing a holding operation to a semiconductor memory array having rows and columns of memory cells, includes: applying an electrical signal to buried regions of the memory cells, wherein each of the memory cells comprises a floating body region defining at least a portion of a surface of the memory cell, the floating body region having a first conductivity type; and wherein the buried region of each memory cell is located within the memory cell and located adjacent to the floating body region, the buried region having a second conductivity type.

Abstract: A page buffer comprises a static latch configured to store data received from an external device, and a dynamic latch configured to receive the data stored in the static latch through a floating node, the dynamic latch comprising a storage capacitor, a write transistor configured to write the data of the floating node to the storage capacitor, and a read transistor configured to read the data of the storage capacitor, and the write transistor and the read transistor sharing the floating node.

Abstract: A semiconductor memory device includes a power decoupling capacitor (PDC) for preventing effective capacitance reduction during a high frequency operation. The semiconductor memory device includes the PDC to which a cell capacitor type decoupling capacitor is connected in series. The PDC includes a metal conductive layer electrically connected in parallel to a conductive layer formed on the same level as a bit line of a cell array region, wherein a plurality of decoupling capacitors in a first group and a plurality of decoupling capacitors in a second group are respectively connected to each other in parallel in a peripheral circuit region, and a storage electrode of the first group and a storage electrode of the second group are electrically connected to each other in series through the conductive layer.

Abstract: An object is to provide a semiconductor device which can hold stored data even when not powered and which achieves high integration by reduction of the number of wirings. The semiconductor device is formed using a material which can sufficiently reduce the off-state current of a transistor, e.g., an oxide semiconductor material which is a wide bandgap semiconductor. When a semiconductor material which allows a sufficient reduction in the off-state current of a transistor is used, data can be held for a long period. One line serves as the word line for writing and the word line for reading and one line serves as the bit line for writing and the bit line for reading, whereby the number of wirings is reduced. Accordingly, the storage capacity per unit area is increased.

Abstract: Disclosed are methods and devices, among which is a device that includes a first semiconductor fin having a first gate, a second semiconductor fin adjacent the first semiconductor fin and having a second gate, and a third gate extending between the first semiconductor fin and the second semiconductor fin. In some embodiments, the third gate may not be electrically connected to the first gate or the second gate.

Abstract: A DRAM controller component generates a timing signal and transmits, to a DRAM, write data that requires a first time interval to propagate from the DRAM controller component to the DRAM and to be sampled by the DRAM on one or more edges of the timing signal, a clock signal that requires a second time interval to propagate from the DRAM controller component to the DRAM, and a write command, associated with the write data, to be sampled by the DRAM on one or more edges of the clock signal. The DRAM controller component includes series-coupled delay elements to generate respective incrementally delayed signals, and a multiplexer to select one of the delayed signals to time the transmission of the write data, such that transmission of the write data is delayed based on a difference between the first time interval and the second time interval.

Abstract: Techniques for providing a semiconductor memory device are disclosed. In one particular exemplary embodiment, the techniques may be realized as an apparatus including a first region and a second region. The apparatus may also include a body region disposed between the first region and the second region and capacitively coupled to a plurality of word lines, wherein each of the plurality of word lines is capacitively coupled to different portions of the body region.

Abstract: A vertical semiconductor device is provided. The semiconductor device includes a cell array including a control bit line connected to cells and electrically isolated from a bit line, and a floating body control circuit for applying a floating control voltage to the control bit line in a predetermined period.

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 configured to hold 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, a capacitor electrically connected to a source electrode or a drain electrode of the transistor is included.

Abstract: A memory capacitor based on a field configurable ion-doped polymer is reported. The device can be dynamically and reversibly programmed to analog capacitances with low-voltage (<5 V) pulses. After the device is programmed to a specific value, its capacitance remains nonvolatile. The field configurable capacitance is attributed to the modification of ionic dopant concentrations in the polymer. The ion and dipole concentrations in the ion conductive layer can be modified when the voltage biases applied to the electrodes exceeds a threshold value and can operate as a conventional capacitor when a voltage less than the threshold value is applied. The ion conductive layer will remain at a stable value after the device is modified without applying external voltage. The device has a nonvolatile memory function even when the external voltage is turned off. The memory capacitors may be used for analog memory, nonlinear analog and neuromorphic circuits.

Abstract: The present invention relates to an electric component comprising at least one first MIM capacitor having a ferroelectric insulator with a dielectric constant of at least 100 between a first capacitor electrode of a first electrode material and a second capacitor electrode of a second electrode material. The first and second electrode materials are selected such that the first MIM capacitor exhibits, as a function of a DC voltage applicable between the first and second electrodes, an asymmetric capacitance hysteresis that lets the first MIM capacitor, in absence of the DC voltage, assume one of at least two possible distinct capacitance values, in dependence on a polarity of a switching voltage last applied to the capacitor, the switching voltage having an amount larger than a threshold-voltage amount. The invention is applicable for ESD sensors, memories and high-frequency devices.

Abstract: A memory cell includes a capacitor, a first transistor, and a second transistor whose off-state current is smaller than that of the first transistor. The first transistor has higher switching speed than the second transistor. The first transistor, the second transistor, and the capacitor are electrically connected in series. Accumulation of charge in the capacitor and release of charge from the capacitor are performed through the first transistor and the second transistor. In this manner, the power consumption of the semiconductor device can be reduced and data can be written and read at higher speed.

Abstract: A semiconductor device comprises a memory cell including a capacitor and a select transistor with a floating body structure, a bit line connected to the select transistor, a bit line control circuit, and a sense amplifier amplifying a signal read out from the memory cell. The bit line control circuit sets the bit line to a first potential during a non-access period of the memory cell, and thereafter sets the bit line to a second potential during an access period of the memory cell. Thereby, the data retention time can be prolonged by reducing leak current at a data storage node of the memory cell so that an average consumption current for the data retention can be reduced.

Abstract: To suppress a timing window from being narrowed undesirably by the harmonic component of a signal output from a semiconductor component without imposing a burden on the semiconductor component that controls access. A capacitor element is arranged in series with a specific transmission path branching from a predetermined node of a signal transmission path and reaching to a ground plane, the signal transmission path supplying an enable control signal that indicates the validity of a clock signal and a command and address signal output from a semiconductor component that controls access on a substrate to another semiconductor component to be accessed on the substrate. The capacitor element functions as a short-circuit path to the ground plane for the harmonic component of the enable control signal and makes smaller the through rate and makes larger the timing window of the enable control signal compared to those when the capacitor element is not provided.

Abstract: An address delay circuit of a semiconductor memory apparatus includes a first group control pulse generation unit configured to generate a first control pulse after input of a first group column address strobe pulse and passage of a time corresponding to a first set multiple of one cycle of a clock, a second group control pulse generation unit configured to generate a second control pulse after input of a second group column strobe address pulse and passage of a time corresponding to a second set multiple of the one cycle of the clock, a first address storage unit configured to receive and store a first group external address in response to the first control pulse, and output a first group internal address, and a second address storage unit configured to receive and store a second group external address in response to the second control pulse, and output a second group internal address.

Abstract: The memory device includes a first logic element which is supplied with a first power supply voltage, and inverts a polarity of a potential of an input terminal to output the potential with the inverted polarity from an output terminal, a second logic element which is supplied with a second power supply voltage supplied through a different path from the first power supply voltage, and inverts a polarity of a potential of an input terminal to output the potential with the inverted polarity from an output terminal, a first memory circuit connected to the input terminal of the first logic element, and a second memory circuit connected to the input terminal of the second logic element. The input terminal and the output terminal of the first logic element are connected to the output terminal and the input terminal of the second logic element, respectively.

Abstract: In a driving method of a semiconductor device which conducts a multilevel writing operation, a signal line for controlling on/off of a writing transistor for conducting a writing operation on a memory cell using a transistor including an oxide semiconductor layer is disposed along a bit line, and a multilevel writing operation is conducted with use of, also in a writing operation, a voltage which is applied to a capacitor at a reading operation. The potential of a bit line is detected while data writing is conducted, and thereby whether a potential corresponding to the written data is normally applied to the floating gate can be confirmed without a writing verify operation.

Abstract: A memory cell comprising a first switch device, a second switch device and a capacitor is disclosed. The first switch device has: a control terminal coupled to a select line, wherein the first switch device is controlled by the select line; a first terminal, coupled to a bit line parallel with the select line. The second switch device has: a first terminal, coupled to the second terminal of the first switch device; a control terminal, coupled to a word line orthogonal to the bit line and the select line, wherein the second switch device is controlled by the word line. The capacitor has a first terminal coupled to the second terminal of the second switch device and a second terminal coupled to a predetermined voltage level, wherein the data is read from the capacitor or written to the capacitor via the bit line.

Abstract: The number of wirings per unit memory cell is reduced by sharing a bit line by a writing transistor and a reading transistor. Data is written by turning on the writing transistor so that a potential of the bit line is supplied to a node where one of a source and drain electrodes of the writing transistor and a gate electrode of the reading transistor are electrically connected, and then turning off the writing transistor so that a predetermined amount of charge is held in the node. Data is read by using a signal line connected to a capacitor as a reading signal line or a signal line connected to one of a source and drain electrodes of the reading transistor as a reading signal line so that a reading potential is supplied to the reading signal line, and then detecting a potential of the bit line.

Abstract: Memory devices and methods of operating memory devices are shown. Configurations described include a memory cell string having an elongated n type body region and having select gates with p type bodies. Configurations and methods shown can provide a reliable bias to a body region for memory operations such as erasing.

Abstract: A semiconductor memory cell array includes a plurality of bit-lines, a plurality of word-lines, a plurality of memory cells, a plurality of dummy memory cells, a plurality of dummy bit-lines, and a plurality of dummy word-lines. The dummy bit-lines are in outer regions of the bit-lines. The dummy word-lines are in outer regions of the word-lines. The dummy bit-lines are maintained in a floating state. The dummy word-lines retain a turn-off voltage.

Abstract: Cross-point memory cells, non-volatile memory arrays, methods of reading a memory cell, methods of programming a memory cell, and methods of writing to and reading from a memory cell are described. In one embodiment, a cross-point memory cell includes a word line extending in a first direction, a bit line extending in a second direction different from the first direction, the bit line and the word line crossing without physically contacting each other, and a capacitor formed between the word line and the bit line where such cross. The capacitor comprises a dielectric material configured to prevent DC current from flowing from the word line to the bit line and from the bit line to the word line.

Abstract: An object is to provide a semiconductor device having a novel structure, which can hold stored data even when not powered and which has an unlimited number of write cycles. A semiconductor device is provided with both a memory circuit including a transistor including an oxide semiconductor (in a broader sense, a transistor whose off-state current is sufficiently small) and a peripheral circuit such as a driver circuit including a transistor including a material other than an oxide semiconductor (in other words, a transistor capable of operating at sufficiently high speed). The peripheral circuit is provided in a lower portion and the memory circuit is provided in an upper portion; thus, the area and size of the semiconductor device can be decreased.

Abstract: A semiconductor device includes a first memory cell, a first line, a second line and a first capacitor. The first line is coupled to the first memory cell. The first line supplies a first voltage to the first memory cell. The second line is supplied with a fixed voltage. The first capacitor is coupled between the first and second lines.

Abstract: A semiconductor memory device includes a plurality of N external ports, each of which receives commands, and an internal circuit which performs at least N access operations during a minimum interval of the commands that are input into one of the external ports.

Abstract: An object is to provide a semiconductor device in which stored data can be retained even when power is not supplied, and there is no limitation on the number of write cycles. The semiconductor device includes a source line, a bit line, a first signal line, a second signal line, a word line, a memory cell connected between the source line and the bit line, a first driver circuit electrically connected to the bit line, a second driver circuit electrically connected to the first signal line, a third driver circuit electrically connected to the second signal line, and a fourth driver circuit electrically connected to the word line and the source line. The first transistor is formed using a semiconductor material other than an oxide semiconductor. The second transistor is formed using an oxide semiconductor material.