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: An EEPROM system having an array of memory cells that individually include two floating gates, bit line source and drain diffusions extending along columns, steering gates also extending along columns and select gates forming word lines along rows of floating gates. The dual gate cell increases the density of data that can be stored. Rather than providing a separate steering gate for each column of floating gates, an individual steering gate is shared by two adjacent columns of floating gates that have a diffusion between them. The steering gate is thus shared by two floating gates of different but adjacent memory cells.

Abstract: An EEPROM device having a plurality of flash EEPROM cells organized in right and left half memory planes each having right and left quad memory blocks is described along with corresponding control circuitry including erase circuitry for concurrently erasing selected addressable data sectors of the EEPROM device. Included in the erase circuitry are a plurality of erase voltage generating circuits, a corresponding plurality of switching circuitry, and switch control circuitry shared by the plurality of switching circuitry for controlling the selectable coupling of erase voltages generated by the erase voltage generating circuits to corresponding data sectors of the EEPROM device.

Abstract: Soft errors occur during normal use of a solid-state memory such as EEPROM or Flash EEPROM. A soft error results from the programmed threshold voltage of a memory cell being drifted from its originally intended level. The error is initially not readily detected during normal read until the cumulative drift becomes so severe that it develops into a hard error. Data could be lost if enough of these hard errors swamps available error correction codes in the memory. A memory device and techniques therefor are capable of detecting these drifts and substantially maintaining the threshold voltage of each memory cell to its intended level throughout the use of the memory device, thereby resisting the development of soft errors into hard errors.

Abstract: Novel memory cells utilize source-side injection, allowing very small programming currents. If desired, to-be-programmed cells are programmed simultaneously while not requiring an unacceptably large programming current for any given programming operation. In one embodiment, memory arrays are organized in sectors with each sector being formed of a single column or a group of columns having their control gates connected in common. In one embodiment, a high speed shift register is used in place of a row decoder to serially shift in data for the word lines, with all data for each word line of a sector being contained in the shift register on completion of its serial loading. In one embodiment, speed is improved by utilizing a parallel loaded buffer register which receives parallel data from the high speed shift register and holds that data during the write operation, allowing the shift register to receive serial loaded data during the write operation for use in a subsequent write operation.

Abstract: A memory array of PROM, EPROM or EEPROM cells has each cell formed in a trench of a thick oxide layer deposited on a silicon substrate, in a manner that a significant portion of opposing areas of the floating gate and control gate of each cell which provide capacitive coupling between them are formed vertically. This allows the density of the array to be increased since the amount of semiconductor substrate area occupied by each cell is decreased without having to sacrifice the amount or quality of the capacitive coupling. Further, a technique of forming capacitive coupling between the floating gate and an erase gate in a flash EEPROM array cell with improved endurance is disclosed.

Abstract: A novel memory structure in which memory arrays are organized in sectors with each sector being formed of a single column or a group of columns having their control gates connected in common. In one embodiment, a high speed shift register is used in place of a row decoder to serially shift in data for the word lines, with all data for each word line of a sector being contained in the shift register on completion of its serial loading. In one embodiment, speed is improved by utilizing a parallel loaded buffer register which receives parallel data from the high speed shift register and holds that data during the write operation, allowing the shift register to receive serial loaded data during the write operation for use in a subsequent write operation.

Abstract: Novel memory cells utilize source-side injection, allowing very small programming currents. If desired, to-be-programmed cells are programmed simultaneously while not requiring an unacceptably large programming current for any given programming operation. In one embodiment, memory arrays are organized in sectors with each sector being formed of a single column or a group of columns having their control gates connected in common. In one embodiment, a high speed shift register is used in place of a row decoder to serially shift in data for the word lines, with all data for each word line of a sector being contained in the shift register on completion of its serial loading. In one embodiment, speed is improved by utilizing a parallel loaded buffer register which receives parallel data from the high speed shift register and holds that data during the write operation, allowing the shift register to receive serial loaded data during the write operation for use in a subsequent write operation.

Abstract: A peripheral card having a Personal Computer ("PC") card form factor and removably coupled externally to a host system is further partitioned into a mother card portion and a daughter card portion. The daughter card is removably coupled to the mother card. In the preferred embodiment, a low cost flash "floppy" is accomplished with the daughter card containing only flash EEPROM chips and being controlled by a memory controller residing on the mother card. Other aspects of the invention includes a comprehensive controller on the mother card able to control a predefined set of peripherals on daughter cards connectable to the mother card; relocation of some host resident hardware to the mother card to allow for a minimal host system; a mother card that can accommodate multiple daughter cards; daughter cards that also operates directly with hosts having embedded controllers; daughter cards carrying encoded data and information for decoding it; and daughter cards with security features.

Abstract: Novel memory cells utilize source-side injection, allowing very small programming currents. If desired, to-be-programmed cells are programmed simultaneously while not requiring an unacceptably large programming current for any given programming operation. In one embodiment, memory arrays are organized in sectors with each sector being formed of a single column or a group of columns having their control gates connected in common. In one embodiment, a high speed shift register is used in place of a row decoder to serially shift in data for the word lines, with all data for each word line of a sector being contained in the shift register on completion of its serial loading. In one embodiment, speed is improved by utilizing a parallel loaded buffer register which receives parallel data from the high speed shift register and holds that data during the write operation, allowing the shift register to receive serial loaded data during the write operation for use in a subsequent write operation.

Abstract: Novel memory cells utilize source-side injection, allowing very small programming currents. If desired, to-be-programmed cells are programmed simultaneously while not requiring an unacceptably large programming current for any given programming operation. In one embodiment, memory arrays are organized in sectors with each sector being formed of a single column or a group of columns having their control gates connected in common. In one embodiment, a high speed shift register is used in place of a row decoder to serially shift in data for the word lines, with all data for each word line of a sector being contained in the shift register on completion of its serial loading. In one embodiment, speed is improved by utilizing a parallel loaded buffer register which receives parallel data from the high speed shift register and holds that data during the write operation, allowing the shift register to receive serial loaded data during the write operation for use in a subsequent write operation.

Abstract: A memory array of PROM, EPROM or EEPROM cells has each cell formed in a trench of a thick oxide layer deposited on a silicon substrate, in a manner that a significant portion of opposing areas of the floating gate and control gate of each cell which provide capacitive coupling between them are formed vertically. This allows the density of the array to be increased since the amount of semiconductor substrate area occupied by each cell is decreased without having to sacrifice the amount or quality of the capacitive coupling. Further, a technique of forming capacitive coupling between the floating gate and an erase gate in a flash EEPROM array cell with improved endurance is disclosed.

Abstract: An EEPROM device having a plurality of flash EEPROM cells organized in right and left half memory planes each having right and left quad memory blocks is described along with corresponding control circuitry including erase circuitry for concurrently erasing selected addressable data sectors of the EEPROM device. Included in the erase circuitry are a plurality of erase voltage generating circuits, a corresponding plurality of switching circuitry, and switch control circuitry shared by the plurality of switching circuitry for controlling the selectable coupling of erase voltages generated by the erase voltage generating circuits to corresponding data sectors of the EEPROM device.

Abstract: Novel memory cells utilize source-side injection, allowing very small programming currents. If desired, to-be-programmed cells are programmed simultaneously while not requiring an unacceptably large programming current for any given programming operation. In one embodiment, memory arrays are organized in sectors with each sector being formed of a single column or a group of columns having their control gates connected in common. In one embodiment, a high speed shift register is used in place of a row decoder to serially shift in data for the word lines, with all data for each word line of a sector being contained in the shift register on completion of its serial loading. In one embodiment, speed is improved by utilizing a parallel loaded buffer register which receives parallel data from the high speed shift register and holds that data during the write operation, allowing the shift register to receive serial loaded data during the write operation for use in a subsequent write operation.

Abstract: Novel memory cells utilize source-side injection, allowing very small programming currents. If desired, to-be-programmed cells are programmed simultaneously while not requiring an unacceptably large programming current for any given programming operation. In one embodiment, memory arrays are organized in sectors with each sector being formed of a single column or a group of columns having their control gates connected in common. In one embodiment, a high speed shift register is used in place of a row decoder to serially shift in data for the word lines, with all data for each word line of a sector being contained in the shift register on completion of its serial loading. In one embodiment, speed is improved by utilizing a parallel loaded buffer register which receives parallel data from the high speed shift register and holds that data during the write operation, allowing the shift register to receive serial loaded data during the write operation for use in a subsequent write operation.

Abstract: Soft errors occur during normal use of a solid-state memory such as EEPROM or Flash EEPROM. A soft error results from the programmed threshold voltage of a memory cell being drifted from its originally intended level. The error is initially not readily detected during normal read until the cumulative drift becomes so severe that it develops into a hard error. Data could be lost if enough of these hard errors swamps available error correction codes in the memory. A memory device and techniques therefor are capable of detecting these drifts and substantially maintaining the threshold voltage of each memory cell to its intended level throughout the use of the memory device, thereby resisting the development of soft errors into hard errors.

Abstract: Soft errors occur during normal use of a solid-state memory such as EEPROM or Flash EEPROM. A soft error results from the programmed threshold voltage of a memory cell being drifted from its originally intended level. The error is initially not readily detected during normal read until the cumulative drift becomes so severe that it develops into a hard error. Data could be lost if enough of these hard errors swamps available error correction codes in the memory. A memory device and techniques therefor are capable of detecting these drifts and substantially maintaining the threshold voltage of each memory cell to its intended level throughout the use of the memory device, thereby resisting the development of soft errors into hard errors.

Abstract: A memory array of PROM, EPROM or EEPROM cells has each cell formed in a trench of a thick oxide layer deposited on a silicon substrate, in a manner that a significant portion of opposing areas of the floating gate and control gate of each cell which provide capacitive coupling between them are formed vertically. This allows the density of the array to be increased since the amount of semiconductor substrate area occupied by each cell is decreased without having to sacrifice the amount or quality of the capacitive coupling. Further, a technique of forming capacitive coupling between the floating gate and an erase gate in a flash EEPROM array cell with improved endurance is disclosed.

Abstract: In a mixed data encoding scheme for programming data into a flash sector of a flash EEPROM system, a method for determining which data encoding scheme has been used for programming the retrieved data involves examining whether an error correction code of the data indicates an error.

Abstract: Various optimizing techniques are used for erasing semiconductor electrically erasable programmable read only memories (EEPROM). An erase algorithm accomplishes erasing of a group of memory cells by application of incremental erase pulses. Techniques include a 2-phase verification process interleaving between pulse applications; special handling of a sample of cells within each erasable unit group; defects handling; and adaptive initial erasing voltages. A streamlined write operation on a flash sector of the EEPROM is implemented by employing the optimized erase in an efficient manner. The write operation includes an initial quick erase of the sector followed by programming of data and verification. Only on those infrequent occasions when a failure occurs as manifested during program verification that the optimized erase will need be evoked.