Abstract: The disclosure concerns electrically programmable memories and, notably, the memories known as EPROMs, EEPROMs, FLASH-EEPROMs. To increase the information storage capacity of a memory, it is proposed to define at least three (instead of two) sections of current coming from a cell to which reading voltages are applied. These sections correspond to n possible programmed states of the cell. Comparators define a piece of information stored, for example, in two-bit form on the outputs S1, S2. However, to ensure safety during the reading despite programming uncertainties, the cell is tested by means of additional comparators and, if the cell current measured for a programming level defined among n levels is too close to the current threshold that defines the programming threshold at this level, an operation for complementary programming of the cell is triggered.

Abstract: An electrically erasable programmable semiconductor memory array for high density including a plurality of column lines; a plurality of reference lines perpendicular to the column lines; a plurality of memory strings arranged in two columns at both sides of each column line and in upper and lower rows between the reference lines, each of upper and lower memory strings at one side of each column including a first transistor and a plurality of floating gate transistors, each of upper and lower memory strings at the other side of each column including a second transistor and a plurality of floating gate transistors, drain-source paths of the first or second transistor and the floating gate transistors in each memory string being connected in series, the first and second transistors and the floating gate transistors being arranged in an array of rows and columns, gates of the first and second transistors and the floating gate transistors in the upper memory strings and the first and second transistors and the flo

Abstract: The disclosure relates to a MOSFET-protected nonvolatile capacitor cell which has a storage gate and a nonvolatile stack thereunder, the cell having a heavily doped n+ ring surrounding the storage gate and an n-type tank disposed beneath the stack and electrically connected to the n+ type ring.

Abstract: Memory transistors are arranged in a plurality of rows and a plurality of columns. A source line is formed for every two bit lines formed in the column direction, each connected to the memory transistors of one column. A source region of each memory transistor is connected, on one side, to a source line adjacent thereto and, on the other side, to a source line through the source region of the adjacent memory transistor, through impurity regions respectively. A floating gate is formed to extend to a position under the corresponding source line. In another example, a source line is formed for each bit line formed in the column direction. The source region of each memory transistor is connected to the adjacent source lines on both sides thereof through impurity regions. The floating gate is formed to extend to positions under both adjacent source lines.

Abstract: An erasable programmable read-only memory with NAND cell structure is disclosed which includes NAND cell blocks each of which has a selection transistor connected to a corresponding bit line and a series array of memory cell transistors. Each cell transistor has a floating gate and a control gate. Word lines are connected to the control gates of the cell transistors. In a data erase mode all the memory cells are simultaneously erased by applying a "H" level potential to the control gates of the memory cells and a "L" level potential to the bit lines. Prior to such a simultaneous erase, charges are removed from charge accumulation layers of the memory cells so that the threshold values of the memory cells are initialized. The threshold initialization is performed on the series-arrayed memory cell transistors in the NAND cell block in sequence.

Abstract: The side wall part of a recess dug in a Si substrate is used as the major part of the electrode surface of a capacitor, whereby the electrode area is enlarged without enlarging a plane area. Thus, a desired capacitor capacitance can be attained without increasing the breakdown of an insulator film ascribable to the conventional approach of thinning of the insulator film. In addition, a vertical switching transistor is formed on the Si substrate, whereby the Si substrate can be entirely utilized for the formation of the capacitor.

Abstract: A memory cell of a nonvolatile semiconductor memory device includes a P conductive type semiconductor substrate, first and second diffusion layers of an N conductivity type, formed in the substrate, a channel region formed in the surface region of the substrate, and which is located between the first and second diffusion layers, a floating gate electrode formed on the channel region, and a control gate electrode formed on the floating gate electrode. The memory cell further includes a third diffusion layer of the N conductivity type, and formed between the first layer and the channel region, the third layer having an impurity concentration lower than that of the first layer.

Abstract: EEPROM memories with crosspoint cells using buried source and drain lines plus merged floating gate transistors with floating gate coupling to control gate over the buried line insulator for high packing plus low voltage operation.

Abstract: A semiconductor memory device is provided with memory cells which each comprises an insulated gate type field effect transistor and a capacitor connected in series with one another and connected to bit lines. The capacitor is composed of a pair of electrodes and a dielectric film which includes a silicon nitride film existing between the pair of electrodes. One electrode of the capacitor is provided with a terminal to which a voltage is applied. The value of the applied voltage is chosen so that the voltage applied between the pair of electrodes is smaller in an absolute value than a voltage applied to the bit line.

Abstract: A zero-power bit circuit comprised in part of a pair of single-level poly transistors having opposite impurity-type channels, the pair connected to accomplish the programming function of a floating-gate transistor. The circuit includes sensing transistors for sensing the presence of absence of charge on the commonly connected gates of a transistor quadruplet comprised of the programming pair and sensing transistors. A diode-connected transistor, an isolation transistor and an inverter-buffer are also included in the bit circuit.

Abstract: A zero-power bit circuit comprised in part of a pair of single-level poly transistors with opposite impurity-type channels, the pair connected to accomplish the programming function of a floating-gate transistor. The circuit includes three programming/isolating transistors and an inverter-buffer.

Abstract: For precise read-out operation at an improved speed, there is disclosed a semiconductor memory device fabricated on a semiconductor substrate of a first conductivity type and including a plurality of memory cells, each memory cell comprising (a) an insulating film covering a surface portion of the semiconductor substrate, (b) a gate electrode formed on the insulating film and located over a channel forming region in the surface portion of the semiconductor substrate, a channel being produced in the channel forming region when the memory cell is selected, (c) a first impurity region having a second conductivity type opposite to the first conductivity type and formed in the surface portion of the semiconductor substrate, the first impurity region being contiguous to the channel forming region or spaced apart from the channel forming region depending upon a bit of information stored therein, and (d) a second impurity region of the second conductivity type formed in the surface portion of the semiconductor substr

Abstract: An N-channel MOS random access memory of the one transistor type is disclosed. The cell utilizes an ion implanted area beneath the capacitor dielectric to permit lower bias voltages on the capacitor. In one example, two levels of polycrystalline silicon are used, one for the bias voltage side of the storage capacitor, and the other for the gate of the MOS transistor and to connect the gate to the bit select line. The capacitor dielectric may be formed of thermal silicon oxide which is about half as thick as the gate insulator of the MOS transistor in the cell. In another example, a single-level poly cell uses an implanted region for the same purpose; the capacitor dielectric is the same thickness as the MOS gate insulator so the lower bias voltage functions to reduce stress failures of the dielectric.

Abstract: The threshold voltage of bit line percharge/equalize MOS transistors is smaller than that of normally ON type bit line pull-up transistors. With this feature, there is no current flows through a bit line from power source V.sub.DD during a read-out operation. The voltage difference between a pair of bit lines can be increased at high speed, thereby increasing the read-out speed.

Abstract: A compact, multi-state field effect transistor (FET) cell having a gate with edge portions of a different conductivity type than a central portion of the gate. Both the edge portions and the central portion extend from the source to the drain of the multi-state FET device. This device would have two different threshold voltages (V.sub.T), one where the central portion would turn on first, followed by the edges for the entire gate width to be active to give a second level of current flow. Such devices would be useful in building very compact or high density multi-state read-only-memories (ROMs).

Abstract: A safety device for an electrically programmable read-only memory of the type comprising a matrix of memory cells, each comprising a floating gate MOS transistor that exhibits a defined threshold voltage after programming, each cell being accessible by rows and columns connected to means which can be used to apply, to these rows and columns, potentials representing the data to be recorded in the cells or potentials representing the command for reading the recorded data. This device comprises at least one reference memory cell included in the memory, the memory cell exhibiting a threshold voltage, after programming, which is lower than the minimum of the dispersal of threshold voltages of the transistors of the matrix.

Abstract: A plurality of logic cells that may be iteratively connected in the form of an array to form an electrically programmable logic device. Each such cell utilizes a plurality of threshold modifiable CMOS transistors as permanent memory storage devices to provide sixteen possible Boolean logic functions for two input variables. The logical operation of the circuit is controlled by simply changing the programming threshold of the memory transistors. These transistors are buffered by drivers and are provided with a switched load transistor. This substantially reduces memory transistor size and power consumption and permits long term program voltage retention. An 18.times.9 cell array embodiment is illustrated along with programming and cell selection logic. A 9.times.9 cell array embodiment is also shown.

Abstract: A semiconductor memory includes memory transistors each having a floating gate is disclosed. This memory is equipped with a detection circuit for detecting a change in the threshold voltage of a selected memory transistor caused by the application of a programming voltage thereto and means responsive to an output of the detection circuit for stopping the application of the programming voltage to the selected memory transistor. A power consumption is thereby reduced in a data writing mode.

Abstract: A decoder circuit fabricated in an IC memory chip and provided to respective word-lines and respective bit-lines of an IC memory matrix fabricated in the IC memory chip, is provided for selecting an EPROM cell which is placed on an intersection point of the word-line and the bit-line, to program a datum into the EPROM cell by using a high power supply voltage when the decoder circuit operates under a programming mode and to read out a datum stored in the EPROM cell by using a low power supply voltage when the decoder circuit operates under a reading mode, receiving an address signal from the exterior of the decoder circuit. The decoder circuit comprises a NAND gate having its load and a CMOS invertor.

Abstract: Using a comparatively low supply voltage of, e.g., +5V and a minus gate voltage, the voltage difference between the gate of an MNOS transistor and a P-type well region in which a MNOS transistor is formed is relatively changed to execute the writing and erasing of the MNOS transistor. Thus, the potential of an N-type semiconductor substrate can be fixed to a comparatively low potential, e.g., about +5V, so that a P-channel MOSFET formed on the semiconductor substrate operates with an ordinary signal level. Consequently, an EEPROM having peripheral circuits constructed of CMOS circuits can be provided. Accordingly, reduction in the power consumption of the EEPROM can be attained.

Abstract: A memory array is organized into rows and columns of memory cells, each cell having a configuration which passes current or blocks current depending upon the state of that cell. The array includes sense circuits to sense cell state. In a preferred embodiment of the invention, an address signal sent to the memory array activates two sets of memory cells connected to the same sense lines, and the threshold level of the sense circuits is set above the level which would be sensed for a failed bit, so that a failed bit appears as if unprogrammed or erased. Because each bit is represented by a pair of memory cells, a failed cell in a pair will not affect operation of the functioning cell in the pair or result in error.

Abstract: A random access memory comprises a semiconductor body of one conductivity type, at least one first well region of an opposite conductivity type formed in the surface area of the semiconductor body, and a memory cell array having a plurality of memory cells formed in the first well region. A peripheral circuit for driving the memory cell array is formed in at least one second well region of the opposite conductivity type formed separately from the first well region in the surface area of the semiconductor body. The second well region is set at a bias level deeper than the first well region.

Abstract: A semiconductor memory device is provided with memory cells which each comprises an insulated gate type field effect transistor and a capacitor connected in series with one another and connected to bit lines. The capacitor is composed of a pair of electrodes and a dielectric film which includes a silicon nitride film existing between the pair of electrodes. One electrode of the capacitor is provided with a terminal to which a voltage is applied. The value of the applied voltage is chosen so that the voltage applied between the pair of electrodes is smaller in an absolute value than a voltage applied to the bit line.

Abstract: Herein disclosed is a semiconductor memory device which is composed of a peripheral circuit unit equipped with a gate protection circuit having a protection resistor and a memory cell unit so that it can be used as an MISFET type static RAM and which is characterized in that the protection resistor is made of a polycrystalline silicon film having substantially the same resistivity as that of an overlying polycrystalline silicon film formed to merge into the load resistor of the memory cell unit.

Abstract: In a semiconductor memory for reading and writing of stored charge in an X-Y address system by arranging a plurality of memory cells each including a capacitance element and one MOS-FET in matrix, this invention discloses a semiconductor memory using multiple level storage structure for read and write of at least more than two multi-level data stored in the capacitance elements, by applying a multi-level step voltage to the plate electrode of the capacitance or to the gate electrode of MOS-FET so as to write and read signal charge.

Abstract: A package for an EPROM provided with an ultraviolet-ray generating layer formed on the surface of an EPROM semiconductor chip to be excited by X-rays or gamma rays to generate ultraviolet rays, and both of the semiconductor chip and the ultraviolet-ray generating layer being sealed with a synthetic resin layer transmitting X-rays or gamma rays.

Abstract: A semiconductor memory device has a semiconductor substrate with a first semiconductor region of one conductivity type in the substrate. A second semiconductor region of the opposite conductivity type is formed in the first semiconductor region. A third semiconductor region of the opposite conductivity type is arranged to be in contact with the first semiconductor region. A fourth semiconductor region of the one conductivity type is formed in the third semiconductor region. A fifth semiconductor region of the one conductivity type, within the semiconductor substrate, has a concentration which is higher than the impurity concentration of the first semiconductor region and is provided under the third semiconductor region. A continuous gate electrode is provided via a gate insulating layer formed on the surface of the first semiconductor region and on the surface of the third semiconductor region.

Abstract: A non-volatile bipolar memory using the technique of comparing selectively degraded bipolar transistor's betas or base-to-emitter voltages to a non-degraded transistor's beta or base-to-emitter voltage to generate desired logic output states from the memory.

Abstract: A bit selectable, two bit per cell memory device using stacked or side-by-side fixed threshold and alterable threshold transistors. The alterable threshold transistors are used both as a switch to select the desired device or memory bank and also as a memory element. Selection between the code represented by the fixed threshold transistors and the code represented by the alterable threshold transistors is prescribed by block erase or block write cycles.

Abstract: A non-volatile dynamic memory cell in which the non-volatile element has two different areas for electron injection, such that direct overwriting of previously stored non-volatile data is permitted without an intervening erase cycle. The non-volatile storage element is a floating gate electrode which has dual control gates disposed thereon. Each control gate includes a layer of dual electron injector structure (DEIS) and a polysilicon gate. When writing a "0" from the volatile storage capacitor to the floating gate, one of the programming gates removes charge from the floating gate. To write a "1", the other programming gate injects charge into the floating gate. The above charge transfer does not take place if the previously stored logic gate and the logic state to be written in are identical.

Abstract: A memory device comprises an electrically conducting substrate having deposited thereon a layer of an amorphous or microcrystalline silicon-carbon alloy and a layer of amorphous or microcrystalline silicon-containing material to form a junction. Preferably the silicon-containing material is silicon and the junction is a heterojunction.The device has fast switching characteristics and good stability.

Abstract: A programmable non-volatile memory cell is disclosed that can be written into the "1," "0," or "previous" state in the presence of unfocused illumination, preferrably ultraviolet (UV) light. The programmed state is controlled by low electrical voltages. Once the illumination is removed the programmed state is non-volatile. The memory cell can be fabricated using conventional MOS processing techniques with no additional mask steps. The cell can thus be implemented on virtually all silicon gate nMOS and CMOS processes.

Abstract: A semiconductor nonvolatile memory wherein a unit cell is constructed of a series connection consisting of an MNOS (metal-silicon nitride-silicon dioxide-semiconductor) transistor whose gate electrode is made of polycrystalline silicon and an MOS (metal-silicon dioxide-semiconductor) transistor whose gate electrode is also made of polycrystalline silicon, such unit cells being arrayed in the form of a matrix, and wherein the gate electrode of the MOS transistor is used as a reading word line, the gate electrode of the MNOS transistor is used as a writing word line, and a terminal of either of the MNOS transistor and the MOS transistor connected in series and constituting the unit cell is used as a data line.

Abstract: A programmable read only memory includes a transistor having an N type source, an N type drain, and a polysilicon floating gate extending over the channel between the source and drain. The floating gate also extends over and is capacitively coupled to an N well. By applying an electric potential to the N well, the potential on the floating gate above the channel is altered.Within the N well is a P region, which mitigates the decrease in capacitive coupling between the N well and the floating gate caused by carrier depletion.

Abstract: A reference circuit which is particularly useful in combination with a memory array in which data transistors are arranged in rows and columns and in which the conduction paths of the data transistors along each column are connected in series between a common ground line and a bit line forming a stack. A problem exists in that the signal current flowing in a stack varies as a function of the position of a selected data transistor along the stack and of the information stored in the other data transistors of the stack. The reference circuit includes means for generating a different reference current corresponding to each row of data transistors along the stacks, where each reference current mirrors and tracks a particular signal condition of the data transistors being sensed in its corresponding row.

Abstract: A memory array is provided which includes a common sense line to which is connected first and second series of cells, each cell of each series includes a storage capacitor, a switching device and a bit line connected to a plate of the storage capacitor, with a common word line connected to the control electrode of each of the switching devices. The switching devices, preferably field effect transistors, of each series of cells have progressively higher threshold voltages beginning at the sense line, and the voltage applied to the common word line has a magnitude greater than that of the highest threshold voltage. Data is stored into or read from the storage capacitors by selecting the common word line and the bit line of the desired cell in a sequential manner.

Abstract: A semiconductor memory device is provided with memory cells which each comprises an insulated gate type field effect transistor and a capacitor connected in series with one another and connected to bit lines. The capacitor is composed of a pair of electrodes and a dielectric film which includes a silicon nitride film existing between the pair of electrodes. One electrode of the capacitor is provided with a terminal to which a voltage is applied. The value of the applied voltage is chosen so that the voltage applied between the pair of electrodes is smaller in an absolute value than a voltage applied to the bit line.

Abstract: A semiconductor device includes storage cells which have a non-volatile storage transistor and an access transistor connected in series therewith, whereby parts of a word (bytes) can be selected for writing and erasing. By means of a second access transistor, which is added to each storage cell, and by means of switches which are controlled by lines used for driving these second access transistors, the current dissipation is reduced and in non-selected storage cells the potential of the insulated control electrodes of the storage transistors is fixed, as a result of which the risk of undesired change of the information content is reduced.

Abstract: A nonvolatile memory which has both the merits of a floating gate type EEPROM and an MNOS type EEPROM and which can be written into and erased with low voltages is disclosed. Each memory element in the nonvolatile memory has a floating gate, a control gate, a gate insulator film between a semiconductor body and the floating gate, and an inter-layer insulator film between the control gate and the floating gate. The gate insulator film is made up of a very thin SiO.sub.2 film and a thin Si.sub.3 N.sub.4 film formed thereon. The charge centroid of charges injected for storing data lies within the floating gate, not within the Si.sub.3 N.sub.4 film.

Abstract: A combined read-only and static read/write semiconductor memory is achieved by modifying the normal threshold voltage of some of the transfer FETs in an otherwise conventional static-memory cell. A read/write data bit is recovered from an addressed cell by applying a word-line voltage higher than both the threshold voltages. Read-only data is read from the same addressed cell by using a word-line voltage higher than one of the thresholds but lower than the other, then decoding the resulting bit-line voltages. An extension allows multiple read-only bits in a single cell by lowering the cell supply voltage when read-only data are addressed.

Abstract: A nonvolatile dynamic RAM capable of operating in a dynamic RAM mode and a second, nonvolatile mode, is disclosed. The nonvolatile dynamic RAM has a memory cell having a transfer transistor for coupling a storage capacitor having a floating gate to a bit line. The memory cell holds information by the storage of charge in the storage capacitor and also holds information by the storage of charge in the floating gate. This data can be stored and retrieved in a volatile mode and in a nonvolatile mode. The nonvolatile dynamic RAM has a plurality of these memory cells connected to a bit line which, in turn, is connected to a sense amplifier for determining the presence or absence of storage charges in the storage capacitor of a selected memory cell in the first mode, and for determining the presence or absence of storage charges in the floating gate of the selected memory cell in the second mode.

Abstract: An electrically alterable non-volatile memory for storing information is described incorporating an array of memory elements comprising N-channel variable threshold field effect transistors having at times an N-channel extending from its source to a predetermined distance from its drain, means for writing information into the array and means for reading information from the array.

Abstract: A non-volatile integrated circuit memory is provided having an array of memory elements selectively programmable to store complimentary binary data, each one of such memory elements being formed in a different region of the integrated circuit and having an address terminal, an output terminal, a ground terminal, and a power supply terminal. Those memory cells programmed into a first logical state are provided with transistor action between the output terminal and the power supply terminal and are inhibited from having transistor action between the output terminal and the ground terminal. Conversely, those memory cells programmed to store the complementary logic state are inhibited from having transistor action between the output terminal and the power supply terminal and are provided with transistor action between the ground terminal and the output terminal. In either programmed state, the transistor action is controlled by signals fed to the address terminal of the cells.

Abstract: A data memory circuit is provided including a plurality of depletion type MOS transistors connected in series, each of which stores data including two bits in the form of a threshold voltage. One end of the memory circuit is kept at a power source level and the second terminal thereof is kept at a ground potential level. 0 V is applied to the gate electrode of one selected MOS transistor while the power source voltage is applied to the gate electrodes of the remaining MOS transistors. As a result, a voltage equal to an absolute value of the threshold voltage of the selected MOS transistor is produced at the second terminal. A converter converts the voltage produced at the second terminal into corresponding binary coded data.

Abstract: A non-volatile memory cell of the MNOS type, in which the sidewalk effect is avoided or at least considerably reduced by limiting the extension of the boundary layer, in which charge is stored, to a region which is smaller than the thin gate dielectric covered by the gate electrode. The gate electrode extends from the active region over a thin insulator, in which no charge storage takes place, to above the thicker field insulation.

Abstract: A programmable memory circuit adapted to access a memory comprises a decoder responsive to address input signals, an access line, a transfer gate connected between the decoder and the access line, and a selective voltage supply circuit connected to the access line. The transfer gate is responsive to a read/write switch signal to connect the decoder to the access line in the read mode and disconnect the decoder from the access line in the write mode. The selective voltage supply circuit is also responsive to the read/write switch signal to provide on the access line different voltage levels in accordance with read/write mode. The access line assumes, in the read mode, one voltage level which is equal to the level of the output signal from the decoder and in the write mode the other voltage level.

Abstract: A novel write circuit arrangement for an EEPROM type memory system operable in response to the difference between the information stored in each addressed cell and the information to the be stored therein during a writing cycle and writing information into only those addressed cells for which a difference exists regardless of whether the difference indicates to charge or discharge the cell. The arrangement also can simultaneously charge one cell of a byte while discharging another cell of the same byte.

Abstract: A non-volatile memory and method is described incorporating an array of variable threshold transistors, a row decoder, a buffer circuit positioned between the array and row decode circuitry, column decode circuitry, and a sense amplifier. The non-volatile memory overcomes the problem of high voltages in the memory array during READ operation. During READ operation the variable threshold transistors operate in the common source mode. A buffer circuit with level shift capability is described incorporating P and N channel transistors. A sense amplifier with decoupling during sensing or lock out is described incorporating P and N channel transistors.

Abstract: A nonvolatile semiconductor memory device has a memory cell array including a MOS FET with a floating gate, first and second control gates and a program electrode; column and row decoders for selecting a specific memory cell; a program control circuit for programming data on the floating gate; and a timing circuit for providing operation timings of the column and row decoders and the program control circuit. The timing circuit sets up a program inhibit period ranging over time point at which a selected memory cell is to be erased and programmed. In the program inhibit period, one of the first and second control gates of each of the memory cells is at a high potential, while the other control gate is at low potential.

Abstract: A quaternary FET read only memory is disclosed wherein each FET storage element in the array has its threshold adjusted by ion-implantation to one of four values. Each FET element in the array has its drain connected to a drain potential V.sub.DD. A binary input signal from a conventional binary, true/complement generator will then enable the gate of a selected FET storage cell and the output potential at the source of that selected storage cell will be V.sub.DD minus the customized threshold voltage of that storage cell, which is output at an output node. The signal on the output node is a quaternary signal which may be amplified by a quaternary sense amplifier circuit and then converted from quaternary to binary signal by means of a converter. The quaternary read only memory is capable of storing twice as much information per unit area as is a conventional FET binary read only memory. The concept may be expanded to N levels of information storage, using FET array devices with N different threshold voltages.