Abstract: An erase operation is performed on a non-volatile memory cell with an oxide-nitride-oxide structure by using a negative gate erase voltage during an erase procedure to improve the speed and performance of the non-volatile memory cell after many program-erase cycles. During the erase procedure, an erase cycle is applied followed by a read cycle until the cell has a threshold erased below a desired value. For the initial erase cycle in the procedure, an initial negative gate voltage is applied. In subsequent erase cycles, a sequentially decreasing negative gate voltage is applied until the threshold is reduced below the desired value. In one embodiment, after erase is complete, the last negative gate voltage value applied is stored in a separate memory. After a subsequent programming when the erase procedure is again applied, the initial negative gate voltage applied is the negative gate voltage value for the cell stored in memory.

Abstract: One aspect of the present invention relates to a non-volatile semiconductor memory device, containing a substrate, the substrate having a core region and a periphery region; a charge trapping dielectric over the core region of the substrate; a gate dielectric in the periphery region of the substrate; buried bitlines under the charge trapping dielectric in the core region; and wordlines over the charge trapping dielectric in the core region, wherein the core region is substantially planar.

Abstract: A system is disclosed for producing an indication of the logical state of a flash memory cell for virtual ground flash memory operations. The system comprises a bit line precharge and hold circuit which is operable to apply and maintain a source terminal voltage (e.g., about 0 volts, ground) to a bit line associated with the source terminal of a cell adjacent to the cell which is sensed during a read operation, wherein the applied source terminal voltage is substantially the same as the bit line virtual ground voltage applied to the source terminal bit line of the selected memory cell to be sensed. The system also includes a drain bit line circuit operable to generate a drain terminal voltage for a drain terminal of a selected memory cell to be sensed.

Abstract: A memory device is disclosed having a memory cell in electrical communication with a node, and operative to indicate a binary value associated with data stored in the memory cell during a read operation when a first voltage is applied to the memory cell. The memory device includes a voltage booster connected between the node and a supply voltage which provides a boosted voltage to the node during the read operation, wherein the boosted voltage is greater than the supply voltage. A method is also disclosed for reading data stored in a memory cell, comprising applying a boosted voltage to a node in electrical communication with the memory cell, wherein the boosted voltage is greater that a supply voltage, and sensing a current associated with the memory cell in order to indicate a binary value associated with data stored in the memory cell during a read operation.

Abstract: A system is disclosed for producing an indication of the logical state of a flash memory cell for virtual ground flash memory operations. The system comprises a bit line charge and hold circuit which is operable to apply a read sense voltage (e.g., about 1.2 volts) to a bit line associated with the drain terminal of a cell of the flash array adjacent to the cell which is sensed, wherein the applied drain terminal voltage is substantially the same as the cell sense voltage (e.g., about 1.2 volts) applied to the drain terminal bit line of the selected memory cell to be sensed.

Abstract: An erase-verify operation is performed on a nonvolatile memory cell with an oxide-nitride-oxide structure by using a low drain bias voltage to allow residual charge remaining in the nitride layer after a typical erase operation to be detected effectively with a high degree of sensitivity.

Abstract: One aspect of the present invention relates to a method of forming a non-volatile semiconductor memory device, involving the sequential or non-sequential steps of forming a charge trapping dielectric over a substrate, the substrate having a core region and a periphery region; removing at least a portion of the charge trapping dielectric in the periphery region; forming a gate dielectric in the periphery region; forming buried bitlines in the core region; and forming gates in the core region and the periphery region.

Abstract: A flash memory formed by a process wherein at least two parallel stacked gate strips are formed on a silicon substrate such that the stacked gate strips are separated by field oxide islands. Asymmetrical first and second junctions are formed in each of a set of source/drain regions and a chemical etch is applied to form the field oxide islands into oxide spacers that align a dual-function control line to the first and second junctions. The resulting flash memory includes a plurality of stacked gate islands, one or more source/drain regions between at least a subset of the plurality of stacked gate islands, first junctions in each of the source/drain regions, second junctions in each of the source/drain regions and dual function control lines in the source/drain regions.

Abstract: Dummy columns of memory cells formed during fabrication outside edge columns are connected to the actual used memory cells of sectors or the like. The columns of dummy memory cells are compensated by floating the dummy memory cells during normal programming and erase cycles, or alternatively, by programming and erasing the dummy memory cells along with the actual used memory cells in the sector. By treating the dummy memory cells similar to the actual used cells, charge that leaks into the dummy cells during fabrication and normal operation that has deleterious effects at higher stress temperatures and/or due to the longevity of customer operation is substantially eliminated.

Abstract: One aspect of the present invention relates to a method of forming a non-volatile semiconductor memory device, involving the sequential or non-sequential steps of forming a charge trapping dielectric over a substrate, the substrate having a core region and a periphery region; removing at least a portion of the charge trapping dielectric in the periphery region; forming a gate dielectric in the periphery region; forming buried bitlines in the core region; removing at least a portion of the charge trapping dielectric positioned over the buried bitlines in the core region; forming a bitline isolation over the buried bitlines in the core region; and forming gates in the core region and the periphery region. Another aspect of the present invention relates to increasing the thickness of the gate dielectric in at least a portion of the periphery region simultaneously while forming the bitline isolation.

Abstract: A bank selector circuit for a simultaneous operation flash memory device with a flexible bank partition architecture comprises a memory boundary option, a bank selector encoder coupled to receive a memory partition indicator signal from the memory boundary option, and a bank selector decoder coupled to receive a bank selector code from the bank selector encoder. The decoder, upon receiving a memory address, outputs a bank selector output signal to point the memory address to either a lower memory bank or an upper memory bank in the simultaneous operation flash memory device, in dependence upon the selected memory partition boundary.

Abstract: One aspect of the present invention relates to a method of forming a non-volatile semiconductor memory device, involving the sequential or non-sequential steps of forming a charge trapping dielectric over a substrate, the substrate having a core region and a periphery region; removing at least a portion of the charge trapping dielectric in the periphery region; forming a gate dielectric in the periphery region; forming buried bitlines in the core region; and forming gates in the core region and the periphery region.

Abstract: One aspect of the present invention relates to a non-volatile semiconductor memory device, containing a substrate, the substrate having a core region and a periphery region; a charge trapping dielectric over the core region of the substrate; a gate dielectric in the periphery region of the substrate; buried bitlines under the charge trapping dielectric in the core region; and wordlines over the charge trapping dielectric in the core region, wherein the core region is substantially planar.

Abstract: An erase operation is performed on a non-volatile memory cell with an oxide-nitride-oxide structure by using an initial negative gate erase voltage to improve the speed and performance of the non-volatile memory cell after many program-erase cycles. By utilizing a negative gate erase voltage, the cell does not require increased erase time to reduce the cell threshold and avoid incomplete erase conditions as the number of program-erase cycles increases.

Abstract: An erase operation is performed on a non-volatile memory cell with an oxide-nitride-oxide structure having charge stored near both the source and drain. During the erase operation, a negative gate erase voltage is applied along with a positive source and drain voltage to improve the speed of erase operations and performance of the non-volatile memory cell after many program-erase cycles.

Abstract: A bank selector encoder comprises a partition indicator circuit having a plurality of partition boundary indicator terminals, a plurality of inverters arranged in a plurality of columns, with each column of the inverters coupled to a respective one of a plurality of columns of ROM cells in a ROM array and a plurality of bank selector code outputs coupled to respective columns of the inverters. The partition boundary indicator terminals are capable of designating a memory partition boundary to identify an upper memory bank and a lower memory bank. The bank selector encoder is capable of generating an identifying bank selector code for each of a plurality of the predetermined memory partition boundaries. The bank selector encoder outputs code bits of a bank selector code based upon the partition boundary indicator terminals.

Abstract: A bank selector circuit for a simultaneous operation flash memory device with a flexible bank partition architecture comprises a memory boundary option, a bank selector encoder coupled to receive a memory partition indicator signal from the memory boundary option, and a bank selector decoder coupled to receive a bank selector code from the bank selector encoder. The decoder, upon receiving a memory address, outputs a bank selector output signal to point the memory address to either a lower memory bank or an upper memory bank in the simultaneous operation flash memory device, in dependence upon the selected memory partition boundary.

Abstract: Control circuitry and a method for generating an accurate drain voltage for selected memory core cells in a semiconductor memory device during a Read mode of operation is provided. Select gate transistors are provided which have their conduction path being coupled between a power supply voltage and a drain of one of the selected memory core cells. A differential amplifier circuit is responsive to a bitline voltage corresponding to a drain voltage of the selected memory core cells and a reference voltage for generating a select gate voltage. The select gate voltage is decreased when the bitline voltage is higher than a target voltage and is increased when the bitline voltage is lower than the target voltage. A source follower circuit is responsive to the select gate voltage for generating the bitline voltage which is maintained at the target voltage.

Abstract: A bank selector circuit for a simultaneous operation flash memory device with a flexible bank partition architecture comprises a memory boundary option 18, a bank selector encoder 2 coupled to receive a memory partition indicator signal from the memory boundary option 18, and a bank selector decoder 3 coupled to receive a bank selector code from the bank selector encoder 2. The decoder 3, upon receiving a memory address, outputs a bank selector output signal to point the memory address to either a lower memory bank or an upper memory bank in the simultaneous operation flash memory device, in dependence upon the selected memory partition boundary.

Abstract: A method of erasing a memory cell that has a first region and a second region with a channel therebetween and a gate above the channel, and a charge trapping region that contains an initial amount of charge. The method includes applying a first voltage across the gate and the first region so that a first portion of the initial amount of charge is removed from the charge trapping region. Next, a second voltage is applied across the gate and the first region so that a second portion of the initial amount of charge is removed from the charge trapping region, wherein the second voltage is different than the first voltage.