Abstract: This invention discloses several embodiments of a low-voltage fast-write NVSRAM cells, made of either of a 2-poly floating-gate type flash cell or a 1-poly charge-trapping SONOS or MONOS flash cell with improvement by adding a Bridge circuit. This Bridge circuit is preferably inserted between each LV 6T SRAM cell and each HV Flash cell that comprises one paired complementary Flash strings. The Flash strings can be made of either 2T or 3T Flash strings. The tradeoff of using either a 2T or a 3T Flash string is subject to the gate area penalty and required design specs. One improvement for adding the Bridge circuit into the NVSRAM cell is to ensure the data writing between Flash cell and SRAM cell with the same polarity and to allow the operation down to low 1.2V Vdd.

Abstract: The present invention provides a two-cycle half-page read scheme by dividing whole NAND array bit lines (BLs) into an odd-BL group and an even-BL group. During the half-plane reading of NAND cells in the odd(even)-BL group, the half-plane even(odd)-BL group acts as the shielding BLs to protect over the odd(even)-BL string reading so that each half-page read operation is substantially reliable and free from BL coupling noise effect. Additionally, each half-page read operation is preferably divided into 3 periods: the first being a bias-condition setup period of the selected WL and remaining control signals; the second being a pre-charge period for all BLs; and the third being a half-page flash data sensing period.

Abstract: A low-current FN channel scheme for erase, program, program-inhibit and read operations is disclosed for NAND NVM memories. This invention discloses a block array architecture and 3-step half-page program algorithm to achieve less error rate of NAND cell threshold voltage level. Thus, the error correction code capability requirement can be reduced, thus the program yield can be increased to reduce the overall NAND die cost at advanced nodes below 20 nm. As a result, this NAND array can still use the LV, compact PGM buffer for saving in the silicon area and power consumption. In addition, the simpler on-chip state-machine design can be achieved with the superior quality of less program errors.

Abstract: A DRAM-like non-volatile memory array includes a cell array of non-volatile cell units with a DRAM-like cross-coupled latch-type sense amplifier. Each non-volatile cell unit has two non-volatile cell devices with respective bit lines and source lines running in parallel and laid out perpendicular to the word line associated with the non-volatile cell unit. The two non-volatile cell devices are programmed with erased and programmed threshold voltages as a pair for storing a single bit of binary data. The two bit lines of each non-volatile cell unit are coupled through a Y-decoder and a latch device to the two respective inputs of the latch-type sense amplifier which provides a large sensing margin for the cell array to operate properly even with a narrowed threshold voltage gap. Each non-volatile cell device may be a 2T FLOTOX-based EEPROM cell, a 2T flash cell, 1 1T flash cell or a 1.5T split-gate flash cell.

Abstract: An integrated circuit formed of nonvolatile memory array circuits, logic circuits and linear analog circuits is formed on a substrate. The nonvolatile memory array circuits, the logic circuits and the linear analog circuits are separated by isolation regions formed of a shallow trench isolation. The nonvolatile memory array circuits are formed in a triple well structure. The nonvolatile memory array circuits are NAND-based NOR memory circuits formed of at least two floating gate transistors that are serially connected such that at least one of the floating gate transistors functions as a select gate transistor to prevent leakage current through the charge retaining transistors when the charge retaining transistors is not selected for reading. Each column of the NAND-based NOR memory circuits are associated with and connected to one bit line and one source line.

Abstract: A NAND-based NOR flash memory array has a matrix of NAND-based NOR flash cells arranged in rows and columns. Every two adjacent NAND-based NOR flash cells in a column share a common source node which is connected to a common source line through a diode. The source line may be made of a metal layer and is in contact directly with the source node or through an ohmic contact to form a Schottky barrier diode. The source line may also be made of a polysilicon or metal layer and connected to the source node through a pillar-structured polysilicon diode and a conduction layer. The diode may also be formed in the source node by enclosing a P/N+ junction diode in a heavily N+ doped region of the source node.

Abstract: A three-dimensional NAND-based NOR nonvolatile memory cell has two three-dimensional SONOS-type charge-retaining transistors arranged in a series string such that one of the charge-retaining transistors functions as a select gate transistor to prevent leakage current through the charge-retaining transistors when the charge-retaining transistors is not selected for determining a data state of the three-dimensional NAND-based NOR nonvolatile memory cell. The first charge retaining transistor's drain is connected to a bit line parallel to the charge retaining transistors and the second charge retaining transistor's source is connected to a source line and is parallel to the bit line.

Abstract: An one-transistor-one-bit (1T1b) Flash-based EEPROM cell is provided along with improved key operation schemes including applying a negative word line voltage and a reduced bit line voltage for perform erase operation, which drastically reduces the high voltage stress on each cell for enhancing the Program/Erase cycles while reducing cell size. An array made by the 1T1b Flash-based EEPROM cells can be operated with Half-page or Full-page divided programming and pre-charging period for each program cycle. Utilizing PGM buffer made of Vdd devices in the cell array further save silicon area. Additionally, a two-transistor-two-bit (2T2b) EEPROM cell derived from the 1T1b cell is disclosed with additional cell size reduction but with the operation of program and erase the same as that for the 1T1b cells with benefits of no process change but much enhanced storage density, superior Program/Erase endurance cycle, and capability for operating in high temperature environment.

Abstract: A single polycrystalline silicon floating gate nonvolatile memory cell has a MOS capacitor and a storage MOS transistor fabricated with dimensions that allow fabrication using current low voltage logic integrated circuit process. The MOS capacitor has a first plate connected to a gate of the storage MOS transistor to form a floating gate node. The physical size of the MOS capacitor is relatively large (approximately 10 time greater) when compared to a physical size of the storage MOS transistor to establish a large coupling ratio (greater than 80%) between the second plate of the MOS capacitor and the floating gate node. When a voltage is applied to the second plate of the MOS capacitor and a voltage applied to the source region or drain region of the MOS transistor establishes a voltage field within the gate oxide of the MOS transistor such that Fowler-Nordheim edge tunnel is initiated.

Abstract: Two-transistor FLOTOX EEPROM cells are collected to form an alterable unit such as a byte. Each of the two-transistor FLOTOX EEPROM cells has a bit line connected to a drain of a select transistor of each of the two-transistor FLOTOX EEPROM cells and a source line placed in parallel with the bit line and connected to a source of a floating gate transistor of each of the two-transistor FLOTOX EEPROM cells. In a program operation, the bit lines are connected to a very large programming voltage level and the source lines are connected to a punch through inhibit voltage level. The punch through inhibit voltage level is approximately one half the very large programming voltage level. The lower drain-to-source voltage level permits the select transistor and the floating gate transistor to have smaller channel lengths and therefore a lower drain-to-source breakdown voltage.

Abstract: An integrated circuit formed of nonvolatile memory array circuits, logic circuits and linear analog circuits is formed on a substrate. The nonvolatile memory array circuits, the logic circuits and the linear analog circuits are separated by isolation regions formed of a shallow trench isolation. The nonvolatile memory array circuits are formed in a triple well structure. The nonvolatile memory array circuits are NAND-based NOR memory circuits formed of at least two floating gate transistors that are serially connected such that at least one of the floating gate transistors functions as a select gate transistor to prevent leakage current through the charge retaining transistors when the charge retaining transistors is not selected for reading. Each column of the NAND-based NOR memory circuits are associated with and connected to one bit line and one source line.

Abstract: A NOR flash nonvolatile memory or reconfigurable logic device has an array of NOR flash nonvolatile memory circuits that includes charge retaining transistors serially connected in a NAND string such that at least one of the charge retaining transistors functions as a select gate transistor to prevent leakage current through the charge retaining transistors when the charge retaining transistors is not selected for reading. The topmost charge retaining transistor's drain is connected to a bit line parallel to the charge retaining transistors and the bottommost charge retaining transistor's source is connected to a source line and is parallel to the bit line. The charge retaining transistors are programmed and erased with a Fowler-Nordheim tunneling process.

Abstract: A nonvolatile memory structure with pairs of serially connected threshold voltage adjustable select transistors connected to the top and optionally to the bottom of NAND series strings of groups of the dual-sided charge-trapping nonvolatile memory cells for controlling connection of the NAND series string to an associated bit line. A first of the threshold voltage adjustable select transistors has its threshold voltage level adjusted to a first threshold voltage level and a second of the threshold voltage adjustable select transistors adjusted to a second threshold voltage level. The pair of serially connected threshold voltage adjustable select transistors is connected to a first of two associated bit lines. The NAND nonvolatile memory strings further is connected to a pair of serially connected threshold voltage adjustable bottom select transistors that is connected to the second associated bit line.

Abstract: A nonvolatile SRAM circuit has an SRAM cell and one or two FLOTOX EEPROM cells connected to the data storage terminals of the SRAM cell. In programming to a first data level, the threshold voltage of a FLOTOX EEPROM transistor is brought to a programmed voltage level greater than a read voltage level and erasing to a second data level, the threshold voltage of the FLOTOX EEPROM transistor is brought to an erased voltage level less than the read voltage level. The nonvolatile SRAM array provides for restoring data to an SRAM cell from a FLOTOX EEPROM memory cell(s) at a power initiation and storing data to the FLOTOX EEPROM memory cell(s) to the SRAM cell at power termination. A power detection circuit for providing signals indicating power initiation and power termination to instigate restoration and storing of data between an SRAM cell and a FLOTOX EEPROM cell(s).

Abstract: A two transistor NOR flash memory cell has symmetrical source and drain structure manufactured by a NAND-based manufacturing process. The flash cell comprises a storage transistor made of a double-poly NMOS floating gate transistor and an access transistor made of a double-poly NMOS floating gate transistor, a poly1 NMOS transistor with poly1 and poly2 being shorted or a single-poly poly1 or poly2 NMOS transistor. The flash cell is programmed and erased by using a Fowler-Nordheim channel tunneling scheme. A NAND-based flash memory device includes an array of the flash cells arranged with parallel bit lines and source lines that are perpendicular to word lines. Write-row-decoder and read-row-decoder are designed for the flash memory device to provide appropriate voltages for the flash memory array in pre-program with verify, erase with verify, program and read operations in the unit of page, block, sector or chip.

Abstract: A nonvolatile memory device includes an array of EEPROM configured nonvolatile memory cells each having a floating gate memory transistor for storing a digital datum and a floating gate select transistor for activating the floating gate memory transistor for reading, programming, and erasing. The nonvolatile memory device has a row decoder to transfer the operational biasing voltage levels to word lines connected to the floating gate memory transistors for reading, programming, verifying, and erasing the selected nonvolatile memory cells. The nonvolatile memory device has a select gate decoder circuit transfers select gate control biasing voltages to the select gate control lines connected to the control gate of the floating gate select transistor for reading, programming, verifying, and erasing the floating gate memory transistor of the selected nonvolatile memory cells.

Abstract: A two transistor NOR flash memory cell has symmetrical source and drain structure manufactured by a NAND-based manufacturing process. The flash cell comprises a storage transistor made of a double-poly NMOS floating gate transistor and an access transistor made of a double-poly NMOS floating gate transistor, a poly1 NMOS transistor with poly1 and poly2 being shorted or a single-poly poly1 or poly2 NMOS transistor. The flash cell is programmed and erased by using a Fowler-Nordheim channel tunneling scheme. A NAND-based flash memory device includes an array of the flash cells arranged with parallel bit lines and source lines that are perpendicular to word lines. Write-row-decoder and read-row-decoder are designed for the flash memory device to provide appropriate voltages for the flash memory array in pre-program with verify, erase with verify, program and read operations in the unit of page, block, sector or chip.

Abstract: An apparatus and method for operating an array of NOR connected flash nonvolatile memory cells erases the array in increments of a page, block, sector, or the entire array while minimizing sub-threshold leakage current through unselected nonvolatile memory cells. The apparatus has a row decoder circuit and a source decoder circuit for selecting the nonvolatile memory cells for providing biasing conditions for reading, programming, verifying, and erasing the selected nonvolatile memory cells while minimizing sub-threshold leakage current through unselected nonvolatile memory cells.

Abstract: An apparatus and method for operating an array of NOR connected flash nonvolatile memory cells erases the array in increments of a page, block, sector, or the entire array while minimizing operational disturbances and providing bias operating conditions to prevent gate to source breakdown in peripheral devices. The apparatus has a row decoder circuit and a source decoder circuit for selecting the nonvolatile memory cells for providing biasing conditions for reading, programming, verifying, and erasing the selected nonvolatile memory cells while minimizing operational disturbances and preventing gate to source breakdown in peripheral devices.

Abstract: A method and apparatus for operating an array block of dual charge retaining transistor NOR flash memory cells by erasing the dual charge retaining transistor NOR flash memory cells to set their threshold voltage levels to prevent leakage current from corrupting data during a read operation. Erasure of the array block of NOR flash memory cells begins by selecting one of block section of the array block and strongly and deeply erasing, over-erase verifying, and programming iteratively until the charge retaining transistors have their threshold voltages between the lower voltage limit and the upper voltage limit of the first program state. Other block sections are iteratively selected and erased, over-erase verified, and programmed repeatedly until the charge retaining transistors have their threshold voltages between the lower voltage limit and the upper voltage limit of the first program state until the entire block has been erased and reprogrammed to a positive threshold level.