Abstract: Non-volatile memory cells store a level of charge corresponding to the data being stored in a dielectric material storage element that is sandwiched between a control gate and the semiconductor substrate surface over channel regions of the memory cells. More than two memory states are provided by one of more than two levels of charge being stored in a common region of the dielectric material. More than one such common region may be included in each cell. In one form, two such regions are provided adjacent source and drain diffusions in a cell that also includes a select transistor positioned between them. In another form, NAND arrays of strings of memory cells store charge in regions of a dielectric layer sandwiched between word lines and the semiconductor substrate.

Abstract: Boosting signals are applied to unselected word lines for a set of NAND strings while a program voltage signal is applied to a selected word line. For a selected NAND string, in a first interval, the drain select gate is opened so that the NAND string communicates with a respective bit line to discharge channel boosting in the NAND string. In a second interval, the drain select gate is closed so that the NAND string is cutoff from the bit line, and the bit line voltage is raised from the level which allows discharging to an inhibit level. In a third interval, the drain select gate is opened again, and the inhibit level of the bit line slows programming. This approach avoids raising the NAND string to a respective starting condition which is based on a source follower action of the drain select gate.

Abstract: One embodiment of the present invention includes applying a first value to a bit line, boosting word lines associated with the bit line and a common selection line to create a first condition based on the first value, and cutting off a boundary non-volatile storage element associated with the common selection line to maintain the first condition for a particular non-volatile storage element associated with the bit line and common selection line. A second value is applied to the bit line and at least a subset of the word lines are boosted to create a second condition for a different non-volatile storage element associated with the bit line and common selection line. The second condition is based on the second value. The first condition and the second condition overlap in time. Both non-volatile storage elements are programmed concurrently, based on their associated conditions.

Abstract: One embodiment of the present invention includes applying a first value to a bit line, boosting word lines associated with the bit line and a common selection line to create a first condition based on the first value, and cutting off a boundary non-volatile storage element associated with the common selection line to maintain the first condition for a particular non-volatile storage element associated with the bit line and common selection line. A second value is applied to the bit line and at least a subset of the word lines are boosted to create a second condition for a different non-volatile storage element associated with the bit line and common selection line. The second condition is based on the second value. The first condition and the second condition overlap in time. Both non-volatile storage elements are programmed concurrently, based on their associated conditions.

Abstract: One embodiment of the present invention includes applying a first value to a bit line, boosting word lines associated with the bit line and a common selection line to create a first condition based on the first value, and cutting off a boundary non-volatile storage element associated with the common selection line to maintain the first condition for a particular non-volatile storage element associated with the bit line and common selection line. A second value is applied to the bit line and at least a subset of the word lines are boosted to create a second condition for a different non-volatile storage element associated with the bit line and common selection line. The second condition is based on the second value. The first condition and the second condition overlap in time. Both non-volatile storage elements are programmed concurrently, based on their associated conditions.

Abstract: A set of storage elements is programmed beginning with a word line WLn adjacent a select gate line for the set. After programming the first word line, the next word line WLn+1 adjacent to the first word line is skipped and the next word line WLn+2 adjacent to WLn+1 is programmed. WLn+1 is then programmed. Programming continues according to the sequence {WLn+4, WLn+3, WLn+6, WLn+5, . . . } until all but the last word line for the set have been programmed. The last word line is then programmed. By programming in this manner, some of the word lines of the set (WLn+1, WLn+3, etc.) have no subsequently programmed neighboring word lines. The memory cells of these word lines will not experience any floating gate to floating gate coupling threshold voltage shift impact due to subsequently programmed neighboring memory cells. The word lines having no subsequently programmed neighbors are read without using offsets or compensations based on neighboring memory cells.

Abstract: Maximized multi-state compaction and more tolerance in memory state behavior is achieved through a flexible, self-consistent and self-adapting mode of detection, covering a wide dynamic range. For high density multi-state encoding, this approach borders on full analog treatment, dictating analog techniques including A to D type conversion to reconstruct and process the data. In accordance with the teachings of this invention, the memory array is read with high fidelity, not to provide actual final digital data, but rather to provide raw data accurately reflecting the analog storage state, which information is sent to a memory controller for analysis and detection of the actual final digital data.

Abstract: A “smart verify” technique, whereby multi-state memories are programmed using a verify-results-based dynamic adjustment of the multi-states verify range for sequential-state-based verify implementations, is presented. This technique can increase multi-state write speed while maintaining reliable operation within sequentially verified, multi-state memory implementations by providing “intelligent” means to minimize the number of sequential verify operations for each program/verify/lockout step of the write sequence. At the beginning of a program/verify cycle sequence only the lowest state or states are checked during the verify phase. As lower states are reached, additional higher states are added to the verify sequence and lower states can be removed.

Abstract: Tracking cells are used in a memory system to improve the read process. The tracking cells can provide an indication of the quality of the data and can be used as part of a data recovery operation if there is an error. The tracking cells provide a means to adjust the read parameters to optimum levels in order to reflect the current conditions of the memory system. Additionally, some memory systems that use multi-state memory cells will apply rotation data schemes to minimize wear. The rotation scheme can be encoded in the tracking cells based on the states of multiple tracking cells, which is decoded upon reading.

Abstract: Tracking cells are used in a memory system to improve the read process. The tracking cells can provide an indication of the quality of the data and can be used as part of a data recovery operation if there is an error. The tracking cells provide a means to adjust the read parameters to optimum levels in order to reflect the current conditions of the memory system. Additionally, some memory systems that use multi-state memory cells will apply rotation data schemes to minimize wear. The rotation scheme can be encoded in the tracking cells based on the states of multiple tracking cells, which is decoded upon reading.

Abstract: For a non-volatile memory system, compressing the erase threshold voltage distribution into the lowest threshold voltage state will decrease the valid data threshold voltage window. Decreasing the valid data threshold voltage window reduces the floating gate to floating gate coupling effect. The compression can be performed as part of the erase process or part of the programming operation.

Abstract: A set of storage elements is programmed beginning with a word line WLn adjacent a select gate line for the set. After programming the first word line, the next word line WLn+1 adjacent to the first word line is skipped and the next word line WLn+2 adjacent to WLn+1 is programmed. WLn+1 is then programmed. Programming continues according to the sequence {WLn+4, WLn+3, WLn+6, WLn+5, . . . } until all but the last word line for the set have been programmed. The last word line is then programmed. By programming in this manner, some of the word lines of the set (WLn+1, WLn+3, etc.) have no subsequently programmed neighboring word lines. The memory cells of these word lines will not experience any floating gate to floating gate coupling threshold voltage shift impact due to subsequently programmed neighboring memory cells. The word lines having no subsequently programmed neighbors are read without using offsets or compensations based on neighboring memory cells.

Abstract: A set of storage elements is programmed beginning with a word line WLn adjacent a select gate line for the set. After programming the first word line, the next word line WLn+1 adjacent to the first word line is skipped and the next word line WLn+2 adjacent to WLn+1 is programmed. WLn+1 is then programmed. Programming continues according to the sequence {WLn+4, WLn+3, WLn+6, WLn+5, . . . } until all but the last word line for the set have been programmed. The last word line is then programmed. By programming in this manner, some of the word lines of the set (WLn+1, WLn+3, etc.) have no subsequently programmed neighboring word lines. The memory cells of these word lines will not experience any floating gate to floating gate coupling threshold voltage shift impact due to subsequently programmed neighboring memory cells. The word lines having no subsequently programmed neighbors are read without using offsets or compensations based on neighboring memory cells.

Abstract: A non-volatile memory device is provided with a controller and includes method that controls memory operations and to emulate the memory and communication characteristics of a legacy memory device. In this way, the memory device is compatible with a host that was originally designed to operate the legacy memory device. In particular, the controller performs the emulation to the host taking into account differences such as multibit memory, error correction requirement, memory support of overwrites, and erasable block sizes.

Abstract: Storage elements are read multiple times and the results are accumulated and averaged for each storage element to reduce the effects of noise or other transients in the storage elements and associated circuits that may adversely affect the quality of the read. Several techniques may be employed, including: A full read and transfer of the data from the storage device to the controller device for each iteration, with averaging performed by the controller; a full read of the data for each iteration, with the averaging performed by the storage device, and no transfer to the controller until the final results are obtained; one full read followed by a number of faster re-reads exploiting the already established state information to avoid a full read, followed by an intelligent algorithm to guide the state at which the storage element is sensed. These techniques may be used as the normal mode of operation, or invoked upon exception condition, depending on the system characteristics.

Abstract: The process for programming a set of memory cells is improved by adapting the programming process based on behavior of the memory cells. For example, a set of program pulses is applied to the word line for a set of flash memory cells. A determination is made as to which memory cells are easier to program and which memory cells are harder to program. Bit line voltages (or other parameters) can be adjusted based on the determination of which memory cells are easier to program and which memory cells are harder to program. The programming process will then continue with the adjusted bit line voltages (or other parameters).

Abstract: A non-volatile memory device is provided with a controller and includes method that controls memory operations and to emulate the memory and communication characteristics of a legacy memory device. In this way, the memory device is compatible with a host that was originally designed to operate the legacy memory device. In particular, the controller performs the emulation to the host taking into account differences such as multibit memory, error correction requirement, memory support of overwrites, and erasable block sizes.

Abstract: An improved flash EEPROM memory-based storage subsystem includes one or more flash memory arrays, each with three data registers and a controller circuit. During a flash program operation, one data register is used to control the program operation, a second register is used to hold the target data value, and a third register is used to load the next sector's data. Subsequent to a flash program operation, a sector's data are read from a flash array into the first data register and compared to the target data stored in the second register. When the data is verified good, the data from the third register is copied into the first and second registers for the next program operation. This creates an improved performance system that doesn't suffer data transfer latency during program operations that require data verification after the program operation is complete. Alternate embodiments perform the comparison using two register implementations and a single register implementations.

Abstract: Non-volatile memory that has non-volatile charge storing capability such as EEPROM and flash EEPROM is programmed by a programming system that applies to a plurality of memory cells in parallel. Enhanced performance is achieved by programming each cell to its target state with a minimum of programming pulses using a data-dependent programming voltage. Further improvement is accomplished by performing the programming operation in multiphase where each successive phase is executed with a finer programming resolution such as employing a programming voltage with a gentler staircase waveform. These features allow rapid and accurate convergence to the target states for the group of memory cells being programmed in parallel, thereby allowing each cell to store several bits of information without sacrificing performance.

Abstract: A non-volatile memory device is programmed by first performing a coarse programming process and subsequently performing a fine programming process. The coarse/fine programming methodology is enhanced by using an efficient verification scheme that allows some non-volatile memory cells to be verified for the coarse programming process while other non-volatile memory cells are verified for the fine programming process. The fine programming process can be accomplished using current sinking, charge packet metering or other suitable means.