Micron Technology Incorporated

Other

Lsi Logic Corporation

Jung-Sheng Hoei

Vishal Sarin

Frankie F Roohparvar

Jonathan Pabustan

William Henry Radke

Kishore Kumar Muchherla

Eric N Lee

Jeffrey S McNeil, Jr

Chia-Shing Jason Yu

Kai Keung Chan

Pankaj Joshi

Leo Fang

Memory devices might include an array of memory cells, a plurality of access lines, and control logic. The array of memory cells includes a plurality of strings of series-connected memory cells. Each access line of the plurality of access lines is connected to a control gate of a respective memory cell of each string of series-connected memory cells of the plurality of strings of series-connected memory cells. The control logic is configured to: open the array of memory cells for multiple read operations; read first page data from respective memory cells coupled to a selected access line of the plurality of access lines; read second page data from the respective memory cells coupled to the selected access line; and close the array of memory cells subsequent to reading the first page data and the second page data.

Memory devices for multiple read operations

Methods for managing data stored in a memory device facilitate managing utilization of memory of different densities. The methods include reading first data from a first number of pages or blocks of memory cells having a first density, performing a data handling operation on the read first data to generate second data, and writing the second data to a second number of pages or blocks of memory cells having a second density, wherein the second density is different than the first density, and wherein the second number is different than the first number.

Data conditioning to improve flash memory reliability

Memory devices adapted to receive and transmit analog data signals representative of bit patterns of two or more bits facilitate increases in data transfer rates relative to devices communicating data signals indicative of individual bits. Programming of such memory devices includes initially programming a cell with a coarse programming pulse to move its threshold voltage in a large step close to the programmed state. The neighboring cells are then programmed using coarse programming. The algorithm then returns to the initially programmed cells that are then programmed with one or more fine pulses that slowly move the threshold voltage in smaller steps to the final programmed state threshold voltage.

Coarse and fine programming in a solid state memory

A memory device that includes a sample and hold circuit coupled to a bit line. The sample and hold circuit stores a target threshold voltage for a selected memory cell. The memory cell is programmed and then verified with a ramped read voltage. The read voltage that turns on the memory cell is stored in the sample and hold circuit. The target threshold voltage is compared with the read voltage by a comparator circuit. When the read voltage is at least substantially equal to (i.e., is substantially equal to and/or starts to exceed) the target threshold voltage, the comparator circuit generates an inhibit signal.

Analog sensing of memory cells in a solid-state memory device

Methods and solid state drives are disclosed, for example a solid state drive that is adapted to receive and transmit analog data signals representative of bit patterns of three or more levels (such as to facilitate increases in data transfer rates relative to devices communicating data signals indicative of individual bits). Programming of the solid state drive, comprising an array of non-volatile memory cells, might include adjusting the level of each memory cell being programmed in response to a desired performance level of a controller circuit.

Programming based on controller performance requirements

An analog-to-digital conversion window is defined by reference voltages stored in reference memory cells of a memory device. A first reference voltage is read to define an upper limit of the conversion window and a second reference voltage is read to define a lower limit of the conversion window. An analog voltage representing a digital bit pattern is read from a memory cell and converted to the digital bit pattern by an analog-to-digital conversion process using the conversion window as the limits for the sampling process. This scheme helps in real time tracking of the ADC window with changes in the program window of the memory array.

Analog-to-digital and digital-to-analog conversion window adjustment based on reference cells in a memory device

Methods of programming memory cells are disclosed. In at least one embodiment, programming is accomplished by applying a first set of programming pulses to program to an initial threshold voltage, and applying a second set of programming pulses to program to a final threshold voltage.

Soft landing for desired program threshold voltage

Methods and apparatus for managing data storage in memory devices utilizing memory arrays of varying density memory cells. Data can be initially stored in lower density memory. Data can be further read, compacted, conditioned and written to higher density memory as background operations. Methods of data conditioning to improve data reliability during storage to higher density memory and methods for managing data across multiple memory arrays are also disclosed.

A memory controller has a digital signal processor. The digital signal processor is configured to output a digital data signal of M+N bits of program data intended for programming a memory cell of a memory device. The digital signal processor is configured to receive a digital data signal of M+L bits read from the memory cell of the memory device and to retrieve from the received digital data signal M bits of data that were stored in the memory cell.

Memory controllers to output data signals of a number of bits and to receive data signals of a different number of bits

In one or more embodiments, a memory device has an adjustable programming window with a plurality of programmable levels. The programming window is moved to compensate for changes in reliable program and erase thresholds achievable as the memory device experiences factors such as erase/program cycles that change the program window. The initial programming window is determined prior to an initial erase/program cycle. The programming levels are then moved as the programming window changes, such that the plurality of programmable levels still remain within the program window and are tracked with the program window changes.

Memory device program window adjustment

In one or more of the disclosed embodiments, memory cells in a memory device are refreshed upon an indication of a fatigue condition. In one such embodiment, controller monitors behavior parameters of the cells and determines if any of the parameters are outside of a normal range set for each one, thus indicating a fatigue condition. If any cell indicates a fatigue condition, the data from the block of cells indicating the fatigue is moved to another block. In one embodiment, an error detection and correction process is performed on the data prior to being written into another memory block.

Refresh of non-volatile memory cells based on fatigue conditions

Self-calibration for a memory controller is performed by writing a voltage to a selected cell. Adjacent cells around the selected cell are programmed. After each of the adjacent programming operations, the voltage on the selected cell is read to determine any change in voltage caused by systemic offsets such as, for example, floating gate-to-floating gate coupling. These changes are averaged and stored in a table as an offset for use in adjusting a programming voltage or a read voltage in a particular area of memory represented by the offset. Self calibration method for temperature is determined by writing cells at different temperatures and reading at different temperatures to generate temperature offset tables for the write path and read path. These offset tables are used to adjust for systematic temperature related offsets during programming and during read.

Memory controller self-calibration for removing systemic influence

Memory devices, methods, and sample and hold circuits are disclosed, including a memory device that includes a sample and hold circuit coupled to a bit line. One such sample and hold circuit includes a read circuit, a verify circuit, and a reference circuit. The read circuit stores a read threshold voltage that was read from a selected memory cell. The verify circuit stores a target threshold voltage that is compared to the read threshold voltage to generate an inhibit signal when the target and read threshold voltages are substantially equal. The reference circuit stores a reference threshold voltage that can be used to translate the read threshold voltage to compensate for a transistor voltage drop and/or temperature variations.

Analog sensing of memory cells with a source follower driver in a semiconductor memory device

Memory devices and methods adapted to process and generate analog data signals representative of data values of two or more bits of information facilitate increases in data transfer rates relative to devices processing and generating only binary data signals indicative of individual bits. Programming of such memory devices includes programming to a target threshold voltage range representative of the desired bit pattern. Reading such memory devices includes generating an analog data signal indicative of a threshold voltage of a target memory cell. Warning of cell deterioration can be performed using reference cells programmed in accordance with a known pattern such as to approximate deterioration of non-volatile memory cells of the device.

Growing community of inventors

Newark, CA, United States of America

Jung-Sheng Hoei