Abstract: The present invention provides an integrated circuit capable of reducing a leak current and reliably holding data therein in a standby mode. A potential higher than a potential of a second source line is supplied to a first source line. A potential lower than a potential of a first ground line is supplied to a second ground line. A virtual source line and a virtual ground line are respectively connected to the second source line and the first ground line by switches in an operation mode and float thereby in the standby mode. Substrates of MOS transistors are respectively connected to the second source line and the first ground line by switches in the operation mode and connected to the first source line and the second ground line thereby in the standby mode. A gate circuit transmits an output signal of a data non-holding circuit to a data holding circuit in the operation mode and fixes an input signal of the data holding circuit in the standby mode.

Abstract: There are many inventions described and illustrated herein. In a first aspect, the present invention is directed to a memory device and technique of reading data from and writing data into memory cells of the memory device. In this regard, in one embodiment of this aspect of the invention, the memory device and technique for operating that device that minimizes, reduces and/or eliminates the debilitating affects of the charge pumping phenomenon. This embodiment of the present invention employs control signals that minimize, reduce and/or eliminate transitions of the amplitudes and/or polarities. In another embodiment, the present invention is a semiconductor memory device including a memory array comprising a plurality of semiconductor dynamic random access memory cells arranged in a matrix of rows and columns.

Abstract: The invention proposes a SRAM memory cell comprising two inverters and, a plurality of switches, the SRAM cell being manufactured in a technology offering N/P shunt capabilities, the inputs of the inverters being connected to at least one pair of bit lines (BLa, BLa/; BLb, BLb/) via two of said switches, said switches being controlled by a signal word line (WLa, WLb), each inverter comprising a first transistor (MN0, MN1) of a first conductivity type and a second transistor (MP0, MP1) of a second conductivity type, and each switch comprising at least a third transistor (MN2, MN3) of the first conductivity type, characterized in that the two transistors (MP0, MP1) of the second conductivity type in the inverters are arranged in two opposite end regions of the memory cell, respectively.

Abstract: An active termination circuit is used to set the input impedance of a plurality of input terminals. Each of the input terminals is coupled to a supply voltage through at least one PMOS transistor and to ground through at least one NMOS transistor. The impedances of the transistors are controlled by a control circuit that generates a first control signal to set the impedance of another PMOS transistor to be equal to a first predetermined resistance, and generates a second control signal to set the impedance of another NMOS transistor to be equal to a second predetermined resistance. The first control signal is used to control all of the PMOS transistors and the second control signal is used to control all of the NMOS transistors. As a result, the PMOS and NMOS transistors coupled to each input terminal have impedances corresponding to the first and second resistances, respectively.

Abstract: There are many inventions described and illustrated herein. In a first aspect, the present invention is directed to a memory device and technique of reading data from and writing data into memory cells of the memory device. In this regard, in one embodiment of this aspect of the invention, the memory device and technique for operating that device that minimizes, reduces and/or eliminates the debilitating affects of the charge pumping phenomenon. This embodiment of the present invention employs control signals that minimize, reduce and/or eliminate transitions of the amplitudes and/or polarities. In another embodiment, the present invention is a semiconductor memory device including a memory array comprising a plurality of semiconductor dynamic random access memory cells arranged in a matrix of rows and columns.

Abstract: An active termination circuit is used to set the input impedance of a plurality of input terminals. Each of the input terminals is coupled to a supply voltage through at least one PMOS transistor and to ground through at least one NMOS transistor. The impedances of the transistors are controlled by a control circuit that generates a first control signal to set the impedance of another PMOS transistor to be equal to a first predetermined resistance, and generates a second control signal to set the impedance of another NMOS transistor to be equal to a second predetermined resistance. The first control signal is used to control all of the PMOS transistors and the second control signal is used to control all of the NMOS transistors. As a result, the PMOS and NMOS transistors coupled to each input terminal have impedances corresponding to the first and second resistances, respectively.

Abstract: There are many inventions described and illustrated herein. In a first aspect, the present invention is directed to a memory cell and technique of reading data from and writing data into that memory cell. In this regard, in one embodiment of this aspect of the invention, the memory cell includes two transistors which store complementary data states. That is, the two-transistor memory cell includes a first transistor that maintains a complementary state relative to the second transistor. As such, when programmed, one of the transistors of the memory cell stores a logic low (a binary “0”) and the other transistor of the memory cell stores a logic high (a binary “1”). The data state of the two-transistor complementary memory cell may be read and/or determined by sampling, sensing measuring and/or detecting the polarity of the logic states stored in each transistor of complementary memory cell.

Abstract: There are many inventions described and illustrated herein. In a first aspect, the present invention is directed to a memory device and technique of reading data from and writing data into memory cells of the memory device. In this regard, in one embodiment of this aspect of the invention, the memory device and technique for operating that device that minimizes, reduces and/or eliminates the debilitating affects of the charge pumping phenomenon. This embodiment of the present invention employs control signals that minimize, reduce and/or eliminate transitions of the amplitudes and/or polarities. In another embodiment, the present invention is a semiconductor memory device including a memory array comprising a plurality of semiconductor dynamic random access memory cells arranged in a matrix of rows and columns.

Abstract: Memory cells are disclosed comprising volatile and non-volatile portions, where the non-volatile portions provide storage of multiple non-volatile data states or bits per memory cell. Methods are provided for reading non-volatile data states from a non-volatile portion of a memory cell into a volatile portion.

Abstract: An active termination circuit is used to set the input impedance of a plurality of input terminals. Each of the input terminals is coupled to a supply voltage through at least one PMOS transistor and to ground through at least one NMOS transistor. The impedances of the transistors are controlled by a control circuit that generates a first control signal to set the impedance of another PMOS transistor to be equal to a first predetermined resistance, and generates a second control signal to set the impedance of another NMOS transistor to be equal to a second predetermined resistance. The first control signal is used to control all of the PMOS transistors and the second control signal is used to control all of the NMOS transistors. As a result, the PMOS and NMOS transistors coupled to each input terminal have impedances corresponding to the first and second resistances, respectively.

Abstract: Method and apparatus are described for providing memory cells enhanced for resistance to single event upsets. In one embodiment, transistors are coupled between cross coupled inverters of a latch, thus in a small area providing both single-event-upset resistivity most of the time, and high speed during writing to the memory cell. Alternatively, inductors coupled between inverters of a latch may be used.

Abstract: A method for writing data to single-transistor capacitorless (1T/0C) RAM cell, wherein the cell structure is predicated on an SOI MOS transistor that has a floating body region (12). Data is written to the cell by the instigation of band-to-band tunneling (BTBT) and the resulting generation of hole/electron pairs. Electrons are drawn from the body region through forward-biased drain (14) and source (15) regions so that holes accumulate in the body region. The increase in threshold voltage, caused by the accumulation of holes, may be defined and detected as a logic level (ONE, for example). In one embodiment, a split biasing scheme applies substantially identical voltages to the drain and to the source and a negative bias to the gate. In alternative embodiments, a negative gate bias is not required and the drain and source bias voltages may be offset so as to mitigate source damage.

Abstract: An active termination circuit is used to set the input impedance of a plurality of input terminals. Each of the input terminals is coupled to a supply voltage through at least one PMOS transistor and to ground through at least one NMOS transistor. The impedances of the transistors are controlled by a control circuit that generates a first control signal to set the impedance of another PMOS transistor to be equal to a first predetermined resistance, and generates a second control signal to set the impedance of another NMOS transistor to be equal to a second predetermined resistance. The first control signal is used to control all of the PMOS transistors and the second control signal is used to control all of the NMOS transistors. As a result, the PMOS and NMOS transistors coupled to each input terminal have impedances corresponding to the first and second resistances, respectively.

Abstract: A semiconductor memory having a memory cell structure capable of reducing soft error without complicating a circuit configuration. Specifically, an inverter (I1) consists of a NMOS transistor (N1) and a PMOS transistor (P1), and an inverter (I2) consists of a NMOS transistor (N2) and a PMOS transistor (P2). The inverters (I1, I2) are subjected to cross section. The NMOS transistor (N1) is formed within a P well region (PW0), and the NMOS transistor (N2) is formed within a P well region (PW1). The P well regions (PW0, PW1) are oppositely disposed with an N well region (NW) interposed therebetween.

Abstract: CMOS I/O structures are described which are latchup-immune by inserting p+ and n+ diffusion guard-rings into the NMOS and PMOS source side of a semiconductor substrate, respectively. P+ diffusion guard-rings surround individual n-channel transistors and n+ diffusion guard-rings surround individual p-channel transistors. These guard-rings, connected to voltage supplies, reduce the shunt resistances of the parasitic SCRs, commonly associated with CMOS structures, from either the p-substrate to p+ guard-ring or the n-well to n+ guard-ring. In a second preferred embodiment a deep p+ implant is implanted into the p+ guard-ring or p-well pickup to decrease the shunt resistances of the parasitic SCRs. The n+ and p+ guard-rings, like the guard-rings of the first preferred embodiment, are connected to positive and negative voltage supplies, respectively.

Abstract: A semiconductor memory device includes a plurality of N and P channel MOS transistors. The plurality of MOS transistors are formed on an SOI (Silicon On Insulator) substrate. Each MOS transistor includes a source region, a drain region, and a body region located between the source region and the drain region. The body region of at least one N channel MOS transistor is electrically fixed. The body region of at least one P channel MOS transistor is rendered floating.

Abstract: A nondestructive read, two-device gain cell for a DRAM memory, based on conventional complementary metal oxide technology is disclosed. The charge is stored on the gate of a first MOSFET, with a second MOSFET connected to the gate for controlling the charge in accordance with an information bit. Depending on the stored charge, the surface under the gate of the first MOSFET is in a depletion or weak inversion condition. For both conditions, the first MOSFET is “off-state.” The first MOSFET causes a bipolar current flow when it is in a weak inversion condition, due to a “read” forward bias of the source to body junction. The bipolar current substantially depends on current gain, thereby multiplying the effective charge read from the first MOSFET.

Abstract: A semiconductor storage device includes: a plurality of first memory arrays each including a plurality of semiconductor storage elements, in which data from an external device is written, and from which the data is read out to the external device, a second memory array which operates separately from the plurality of first memory arrays and which includes at least one block including a plurality of non-volatile semiconductor storage elements; and a data transfer section for transferring the data between the plurality of first memory arrays and the second memory array.

Abstract: A technique for reducing leakage current in static CMOS devices by adding additional transistors in series between selected inverters or logic gates and ground or power. NMOS and PMOS transistors are added to selected buffers comprised of two inverters in series. The PMOS transistor is connected between the first inverter and power and the NMOS transistor is connected between the second inverter and ground. The added transistors are controlled by a memory cell to be on when the buffer is being used and off when the buffer is unused. Alternatively, no PMOS transistor is added and an existing PMOS transistor of the first inverter is manufactured to sit in a Vgg well. The same techniques are employed with selected buffer pairs and logic gates.

Abstract: To establish whether a precharged node remains isolated or alternatively is subject to discharge, the conventional circuit allows uncertainty. For a period after evaluation starts, the conventional circuit will give a tentative result that may subsequently turn out to be wrong. During evaluation power is dissipated. A differential offset dynamic comparator and timing circuit are used to evaluate whether the node is being discharged. Because the comparator has an offset, much smaller deviations from the precharge potential can be sensed: because it is dynamic, it does not consume steady state current. The timing circuit permits precise knowledge of when to look at the output: before the timing period has elapsed, the result is known to be invalid.

Abstract: A memory cell has a pair of n-ch drive MOS transistors, a pair of p-ch access MOS transistors. The access MOS transistor supply electric charge to storage nodes of the drive MOS transistors without using a resistive load. The gate insulation films of the drive MOS transistors have a thickness lower than the thickness of the gate insulation films of the access MOS transistors for achieving stable and high-speed operation of the memory cell.

Abstract: CMOS I/O structures are described which are latchup-immune by inserting p+ and n+ diffusion guard-rings into the NMOS and PMOS source side of a semiconductor substrate, respectively. P+ diffusion guard-rings surround individual n-channel transistors and n+ diffusion guard-rings surround individual p-channel transistors. These guard-rings, connected to voltage supplies, reduce the shunt resistances of the parasitic SCRs, commonly associated with CMOS structures, from either the p-substrate to p+ guard-ring or the n-well to n+ guard-ring. In a second preferred embodiment a deep p+ implant is implanted into the p+ guard-ring or p-well pickup to decrease the shunt resistances of the parasitic SCRs. The n+ and p+ guard-rings, like the guard-rings of the first preferred embodiment, are connected to positive and negative voltage supplies, respectively.

Abstract: A semiconductor memory with static memory cells has an n-well in which pMOS transistors are formed and a p-well in which nMOS transistors are formed. The n- and p-wells are divided into blocks each containing a given number of memory cells. The n- and p-wells in each block receive voltages that vary depending on whether or not the memory cells are selected. If the memory cells are selected to operate, the threshold voltage of each transistor in the memory cells is decreased to increase current to be taken out of the memory cells. If the memory cells are not selected, the threshold voltage is increased to reduce leakage current of the memory cells. This arrangement suppresses standby current and improves the operation speed of the memory cells.

Abstract: A pair of dummy signal lines transmitting dummy signals, complementary to and synchronized with a normal signal, are arranged to form a set together with a normal transfer line transmitting the normal signal. In a device on a receiving side, one of the dummy signal lines is selected and coupled in accordance with the logic level of the normal signal, whereby two ringings occur in the opposite phases on the receiving side, and cancel each other so that ringing of the normal signal can be suppressed. An input/output interface, which can transfer a signal having a short level transition time without causing ringing, can be provided.

Abstract: CMOS circuits are made resistant to erroneous signals produced by the impact of high energy charged particles (commonly known in the literature as Single Event Upset or SEU) by the addition of upset immune transistor structures into the circuits in such a way that they block and dissipate the erroneous signal. The added transistor structures are made immune to SEU by placing them in well diffusions that are separate from the rest of the circuit and biasing those wells such that the electric fields surrounding the transistors are very low in comparison to the rest of the circuit. Signal blocking is achieved with an SEU immune transistor that is in an “off” state whenever other circuit transistors that deliver signals through it are potentially sensitive to SEU. Dissipation is achieved with either a resistor or low current drive transistor that spreads the SEU signal out over time thereby reducing its voltage change to an acceptable level.

Abstract: A masked ROM of a flat cell structure has a plurality of bit-line diffusion layers formed in parallel in one direction in a semiconductor. substrate, a plurality of word lines formed on the bit-line diffusion layers orthogonally to the bit-line diffusion layers and channel regions between the bit-line diffusion layers beneath the word lines, wherein the word line is composed of a laminated layer of a first conductive layer and a second conductive layer on the channel regions and composed of the second conductive layer on the bit-line diffusion layers.

Abstract: A single event upset hardened memory cell to be utilized in static random access memories is disclosed. The single event upset hardened memory cell includes a first set of cross-coupled transistors, a second set of cross-coupled transistors, a first set of isolation transistors, and a second set of isolation transistors. The first and second sets of isolation transistors are coupled to the first and second set of cross-coupled transistors, respectively, such that two inversion paths are formed between the cross-coupled transistors and the isolation transistors.

Abstract: A field effect transistor (FET) is formed on a silicon on insulator (SOI) substrate in the thin silicon layer above the insulating buried oxide layer. A clock signal defines a clock period with an active portion and a wait portion. The source region and/or the drain region are coupled to a body pumping signal. The body pumping signal includes a negative voltage pulse occurring during the wait portion which sets the voltage of a body region of the FET to a preset voltage during such negative voltage pulse. Decay of the preset voltage is predictable such that operation of the FET can be controlled during the active portion.

Abstract: The present invention relates to the use of a conventional MOS transistor as a memory point in which, during programming, the well of the MOS transistor is connected to a reference potential, the drain and the source are connected to a current source adapted to bias the drain and source junctions in reverse and in avalanche so that the space charge region extends along the entire channel length, the gate is set to the reference potential if the memory point does not have to be programmed and to a distinct potential if the memory point has to be programmed; and during the reading, circuitry is provided to detect a high or low impedance state between the gate and the well.

Abstract: A CMOS device and process are disclosed in which two types of N-channel MOS transistors are provided, one being formed in a P-well and one being formed outside the P-well where the relatively low doping concentration of P-type substrate serves as a channel defining region. This second type N-channel transistor an support higher junction voltages due to the lower p-type doping concentration than is possible for the first type N-channel transistor formed in the higher doping concentration P-well. A mask is provided to prevent boron doping in the substrate at the site of the high voltage transistor during the implantation step which defines the P-well.

Abstract: A memory cell in which data is written and read from a pass gate. The memory cell has a connection to a first pass gate, connecting the memory cell to a bit line. Additionally, the memory cell has a second pass gate connecting the memory cell to a complementary bit line. The pass gates are controlled by a word line and a complementary word line.

Abstract: A two-MOSFET device memory cell, based on conventional SOI complementary metal oxide technology, in which charge is stored on the body of a first MOSFET, with a second MOSFET connected to the body for controlling the charge in accordance with an information bit. Depending on the stored charge, the body of the first MOSFET is in depletion or non-depletion condition. A reference voltage connected to the gate of the first MOSFET causes a bipolar current flow in response to a pulsed voltage on the first MOSFET's source when the MOSFET is in a non-depletion condition, due to a temporary forward bias of the source to body junction. The bipolar current substantially adds to the field-effect current, thereby multiplying the effective charge read from the first MOSFET.

Abstract: A CMOS integrated circuit that comprises a graphics controller system that consists of a graphics engine and video memory together with some interface blocks, a PCMCIA host adapter, an infrared interface for generating video images on a LCD or CRT display unit, and a video stream interface for receiving video signals. Since the video memory is integrated on the same integrated circuit as the graphics controller, no package pins are required for the memory interface. The pins thus saved are used to provide access to an on-chip PCMCIA host adapter. The internal memory interface is 128 bits wide. Simultaneous performance improvement and power dissipation reduction is achieved because of the wide memory interface and the elimination of the large parasitic capacitances associated with a package pin connection.

Abstract: In a non-volatile semiconductor memory device having a writing power source voltage which is supplied thereto exceeding a withstand voltage of a field effect transistor, the object of the present invention is to reduce the number of kinds of field effect transistors constituting the non-volatile semiconductor memory device thereby reducing manufacturing cost. In a non-volatile semiconductor memory device which has a writing circuit 125 for controlling a connection of a writing load to a bit line designated by an output of a column decoder 117 in accordance with a signal of a writing data line 114, and a bias circuit 118 for outputting a bias voltage to set a cell writing voltage of a memory cell array by reducing the writing power source voltage.

Abstract: A semiconductor memory device is obtained having a triple well structure improved by preventing latch up or the like. In this semiconductor memory device, a substrate potential is applied to a p type well region in a memory cell region through a p.sup.+ type impurity region and a ground potential is applied to a p type well region in a peripheral circuit region through the P.sup.+ type impurity region. By this structure, the peripheral circuit region including a complementary type field effect transistor having the possibility of generation of latch up is kept at a stable potential even at the time of power-on. Further, since the substrate potential generated by internal circuitry is applied to a first well region of the memory cell region, reliable operation of the memory cell region is maintained.

Abstract: The invention concerns a memory cell insensitive to disturbances. The memory cell, that contains information in the form of two complementary logical levels (X, C(X)), each logical level being stored in a node of the cell (N1, N2), is characterized in that it comprises means of storing the same logical level in two different nodes (N1, N2, N3, N4), the said means being able to restore any logical level to its initial state preceding a modification made on it due to a disturbance, as a result of holding the value of one of the two logical levels complementary to the logical level that was modified.

Abstract: A method and a circuit for fast equilibration of complementary data lines in memory circuit following a write cycle. The circuit of the present invention separately controls the on/off timing of pull-up and pull-down transistors coupled to the data lines to obtain faster equilibration. In one embodiment incorporating an equilibration transistor between the data lines, the pull-up transistor coupled to the high data line is momentarily turned off after a write cycle, to allow the voltage on the high data line to drop all the way down to the voltage on the recovering low data line to reduce equilibration delay.

Abstract: Disclosed is a static type memory cell with high immunity from alpha ray-induced soft errors. The memory cell has a coupling capacitance C.sub.c between two data storage nodes 1 and 2. The p-well (or p-substrate) in which the driver-MOS transistors MN3, MN4 and the transfer MOS transistors MN1, MN2 are formed is connected to a V.sub.bb generator. The voltage V.sub.bb is set lower than the low level V.sub.L of the memory cell signal potential. Even when the potential variation .DELTA.V.sub.L of the low-voltage side node 2 is large, the parasitic diode present between the n-type diffusion layer corresponding to the source or drain of MN1-MN4 and the p-well (or p-substrate) does not turn on. Erroneous operations can therefore be prevented.

Abstract: Adjacent memory cells has a two-layer structure formed of first layer and second layer. The first layer is provided with driver transistors of the memory cell, access transistors of the memory cell, and driver transistors formed of the memory cell. The second layer is provided with load transistors of the memory cell, load transistors and of the memory cell, and access transistors of the memory cell. The transistors formed in the first layer are of an NMOS type, and the transistors formed in the second layer are of a PMOS type.

Abstract: A method and a circuit for fast equilibration of complementary data lines in memory circuit following a write cycle. The circuit of the present invention separately controls the on/off timing of pull-up and pull-down transistors coupled to the data lines to obtain faster equilibration. In one embodiment incorporating an equilibration transistor between the data lines, the pull-up transistor coupled to the high data line is momentarily turned off after a write cycle, to allow the voltage on the high data line to drop all the way down to the voltage on the recovering low data line to reduce equilibration delay.

Abstract: A semiconductor memory device is provided which has a plurality of memory cells each including a pair of cross-coupled metal insulated gate field effect transistors having channels of N-conductivity type, and a pair of load resistors of polycrystalline silicon respectively coupled to the pair of cross-coupled transistors. A peripheral circuit is also provided which is constituted by metal insulated gate field effect transistors having channels of the N-conductivity type and metal insulated gate field effect transistors having channels of P-conductivity type. The semiconductor memory device is formed in an N-type semiconductor substrate, and the pair of cross-coupled metal insulated gate field effect transistors of the memory cells are formed in a well region of P-type which forms a PN-junction with the semiconductor substrate to help reduce the susceptibility to soft errors.

Abstract: A static read-only-memory (ROM) is derived from a gate array in which both P-channel transistor (24) and an N-channel transistor (30) are used to convey a logic 1 or 0 to a bitline (Bitline0). The invention maximizes the use of gate array transistors in a gate-array chip and achieves a high density of ROM bits per unit area. In CMOS gate arrays, transistors are arrayed in alternating rows of P-channel and N-channel transistors. A decoding scheme inverts the logic signal to each row of P-channel transistors to yield a functional ROM.

Abstract: A CMOS circuit formed in a semiconductor substrate having improved immunity to radiation induced latch-up and improved immunity to a single event upset. The circuit architecture of the present invention can be utilized with N-Well, P-Well and dual Well processes. For example, the circuit is described relative to an N-Well process. An N-Well is formed in a p-type substrate. A network of p-channel transistors are formed in the N-Well and a network of n-channel transistors are formed in the p-type substrate. A continuous P+guard ring is formed surrounding the n-channel transistors and between the n-channel transistors and the N-Well. Similarly, a continuous N+guard ring is formed surrounding the p-channel transistors and between the p-channel transistors and the p-type substrate. In the event of a radiation hit, the guard rings operate to reduce the parasitic impedance in the collector circuits of the parasitic bipolars forming a parasitic SCR and also act as additional collectors of radiation induced current.

Abstract: A memory cell for storing data includes a first field effect transistor having a source receiving a first voltage, a floating gate, and a drain receiving data to be written into the memory cell and outputting the data, and a second field effect transistor having a source receiving a second voltage, a floating gate connected to the floating gate of the first field effect transistor, and a drain connected to the drain of the first field effect transistor. The second field effect transistor has a conduction type opposite to that of the first field effect transistor. The memory cell has a capacitor which has a first terminal receiving a select signal for identifying the memory cell, and a second terminal connected to the floating gates of the first and second field effect transistors. The data is stored in the floating gates of the first and second field effect transistors.

Abstract: In a semiconductor integrated circuit device having a data latch function, one of two inverters constituting a data latch circuit is formed of a PMOS transistor and an NMOS transistor, with the source terminal of the NMOS transistor being connected to a terminal for applying a reset signal. The reset signal is applied to an inverter through the NMOS transistor, and the inverter inverts the reset signal and resets the data latch circuit. Since one inverter of the data latch circuit is formed of the PMOS transistor and the NMOS transistor, the setting/resetting function of the semiconductor integrated circuit device can readily be implemented.

Abstract: A structure of a thin film transistor capable of reducing the power consumption in the waiting state and stabilizing the data holding characteristic in application of the thin film transistor as a load transistor in a memory cell in a CMOS-type SRAM is provided. A gate electrode is formed of a polycrystalline silicon film on a substrate having an insulating property. A gate insulating film is formed on the gate electrode. A polycrystalline silicon film is formed on the gate electrode with the gate insulating film interposed therebetween. Source/drain regions including a region of low concentration and a region of high concentration are formed in one and another regions of the polycrystalline silicon film separated by the gate electrode. Thus, the thin film transistor is formed. The thin film transistor is applied to p-channel MOS transistors serving as load transistors in a memory cell of a CMOS-type SRAM.

Abstract: An object of the present invention is to provide a semiconductor integrated circuit in which an EEPROM is incorporated in a highly integrated microcomputer having a twin well structure. A twin well region including an n-well region, a p-well region, and a p-type substrate region surrounded by a p-well region are produced in a single semiconductor substrate. A supply voltage system made up of a CPU, a ROM or RAM, a UART, and EEPROM control systems to which the high voltage for the EEPROM is not applied is formed in the twin well region as a CMOS structure, enabling high density integration. A high-voltage system made up of an EEPROM memory cell array and an EEPROM peripheral high-voltage system in the p-type region have an NMOS structure. This arrangement minimizes the substrate effect and enables the high-voltage system to operate normally.

Abstract: A highly integrated semiconductor memory device, such as a DRAM, is provided with a unique triple-well structure which results in reduced junction capacitance of transistors and a smaller body effect. The semiconductor memory device comprises first and second wells of a first conductivity type and a third well of a second conductivity type formed in a semiconductor substrate of the first conductivity type. The first well is formed in the third well and the first well and the second well are connected to receive a ground level Vss well bias voltage and a negative level V.sub.BB well bias voltage, respectively. A plurality of MOS transistors of the first conductivity type are formed in the third well and at least two series-connected MOS transistors of the second conductivity type are formed in the first well. A plurality of MOS transistors of the second conductivity type and a plurality of memory cells are also formed in the second well.

Abstract: An asymmetric static random access memory cell (50 and 53) includes polysilicon load elements (55 and 56), N-channel pull-down transistors (57 and 58), and N-channel coupling transistors (59 and 60). One of the coupling transistors (59 and 81) has a channel width that is less than the channel width of the other coupling transistor (60 and 80). The asymmetric cells (50 and 53) are located close to power supply voltage terminal V.sub.SS, while conventional symmetrical cells (51 and 52) are located apart from the power supply voltage terminal V.sub.SS. The asymmetric cells (50 and 53) correct an imbalance in the ground path caused by a parasitic resistance (83 and 86) of a diffusion layer (94) that is used to couple the asymmetric cells (50 and 53) to ground potential. The asymmetric cell (50 and 53) improves cell stability without degrading performance or increasing cell area.

Abstract: A semiconductor memory device is provided which has a plurality of memory cells each including a pair of cross-coupled metal insulated gate field effect transistors having channels of N-conductivity type, and a pair of load resistors of polycrystalline silicon respectively coupled to the pair of cross-coupled transistors. A peripheral circuit is also provided which is constituted by metal insulated gate field effect transistors having channels of the N-conductivity type and metal insulated gate field effect transistors having channels of P-conductivity type. The semiconductor memory device is formed in an N-type semiconductor substrate, and the pair of cross-coupled metal insulated gate field effect transistors of the memory cells are formed in a well region of P-type which forms a PN-junction with the semiconductor substrate to help reduce the susceptibility to soft errors.