Sandisk Technologies Inc.

Kenneth Louie

Khanh Vinh Nguyen

Man Lung Mui

Grishma Shah

Yan Li

Jian Feng Chen

Nian Niles Yang

Chang Hua Siau

Tai-Yuan Tseng

Qui V Nguyen

Jong Hak Yuh

Anirudh Amarnath

Kapil Verma

Hao Nguyen

Ali K Al-Shamma

Jixin Yu

Farookh Moogat

Gopinath Balakrishnan

Ohwon Kwon

James B Hart

Yen-Lung Li

Alexander Chu

A memory device and associated techniques improve a settling time of bit lines in a memory device during a sensing operation, such as read or verify operation. Supply voltage from power supply terminals in the sense circuits is briefly toggled during a discharge of a selected bit line in response to a voltage on a selected word line being increased to a second word line level or higher. This helps to create an electrical path from the selected bit line through to a supply terminal for discharging the selected bit line such that a settling time of a voltage of the selected bit line is shortened in association with a target memory cell transitioning from a non-conductive state to a conductive state.

Toggling power supply for faster bit line settling during sensing

This disclosure provides a method and apparatus for applying a dynamic strobe signal to a plurality of sense modules during programming of an array of memory cells, where a characteristic of the dynamic strobe signal is configured to limit a peak current level through the plurality of sense modules. An example apparatus the array of memory cells, a plurality of bit lines spanning the array of memory cells, and the plurality of sense modules connected to the bit lines. The plurality of sense modules enable sensing of states of memory cells. A controller determines the characteristic of the dynamic strobe signal, where the dynamic strobe signal is varied based on the determined characteristic.

Loop control strobe skew

Apparatuses, systems, and methods are disclosed for three-dimensional non-volatile memory. A stack of word line layers includes word lines for a three-dimensional non-volatile memory array. A stack of word line layers may include a plurality of tiers. Word line switch transistors transfer word line bias voltages to the word lines. Word line contact regions couple word line switch transistors to word lines. A word line contact region includes a stepped structure for a tier of word line layers. A level region separates a word line contact region for a first tier from a word line contact region for a second tier.

Word line contact regions for three-dimensional non-volatile memory

Read operations are performed in a multi-plane memory device. A state machine interfaces an external controller to each plane of memory cells to allow reading from selected word lines in the planes. In one approach, different types of read operations are performed in different planes, such as a multi-level cell read, e.g., a lower, middle or upper page read and a single-level cell (SLC) read. When the read operation in one plane uses fewer read voltages than another plane, the read data can be output early from the one plane while read operations continue on the other plane. The external controller can also command a cache release for one plane after outputting data from the caches of another plane. Read voltages can be set for each plane in a respective set of registers.

Independent multi-plane read and low latency hybrid read

Techniques are presented for the programming of a non-volatile memory in which multi-state memory cells use a charge trapping layer. When writing data onto a word lines, different data states are written individually, while programming inhibiting the other states, thereby breaking down the write operation into a number of sub-operations, one for each state to be written. This allows for improved timing and decreased power consumption.

Programming techniques for non-volatile memories with charge trapping layers

Systems and methods for reducing peak power supply current in a non-volatile memory system that includes a plurality of memory die are described. In some cases, prior to a first memory die of the plurality of memory die performing a particular memory operation (e.g., a programming operation), the first memory die may poll other memory die of the plurality of memory die to determine a total peak power supply current for the plurality of memory die. In response to detecting that the total peak power supply current for the plurality of memory die is at or above a peak current threshold (e.g., more than 200 mA), the first memory die may delay the performance of the particular memory operation or slow down the performance of the particular memory operation.

Ad hoc digital multi-die polling for peak ICC management

When performing an erase on a flash type non-volatile memory with a NAND type of structure, techniques are presented for inhibiting erase on selected word lines, select lines of programmable select transistors, or some combination of these. The voltage along the selected control lines are initially ramped up by the level on a corresponding input line, but then have their voltage raised to an erase inhibit level by capacitive coupling with the well structure. The level of these input signals are ramped up with the erase voltage applied to the well structure, but with a delay based upon the coupling ratio between the control line and the well.

Time domain ramp rate control for erase inhibit in flash memory

Determining dynamic read levels for memory cells is disclosed. A group of memory cells may be read at a pair of reference levels. Results of reading the group at the pair of reference levels are compared while the group is read at a different reference level. By comparing the results of reading the group at the pair of reference levels while reading the group at a different reference level, time is saved. Note that the reading and comparing can be repeated for other pairs of reference levels. The storage device may determine an adjusted read level based on the comparisons of the results for the different pairs of reference levels. The memory cells may be read at a set of reference levels. A voltage on a word line is not back down to ground between the reads in one aspect, which saves considerable time.

Dynamic read valley search in non-volatile memory

Rather than supply an internal node of a non-volatile memory's sense amplifier from a supply level through a transistor by applying a voltage to the transistor's gate to clamp the node, the internal node is supplied by an op-amp through a pass gate. The op-amp receives feedback from above the pass gate. This allows a desired voltage level to be more quickly and accurately established on the node. Using a two-step reference level for the op-amp can further increases speed and accuracy. Biasing the op-amp with the external power supply can offer additional advantages.

Operational amplifier methods for charging of sense amplifier internal nodes

When applying a sensing voltage at one end of a word line of a non-volatile memory circuit, an initial kick, where the voltage is initially raised somewhat above its final desired voltage, is used. Using on-chip circuitry for the determination of the RC time constant of the word lines allows for this kick to be trimmed to the specifics of the circuit. To further improve settling times for read operations is NAND type architectures, when raising the voltage to the desired read level on a selected word line, a reverse kick, where the non-selected word line's voltage is dropped briefly, can be applied to neighboring non-selected word lines.

Word line kick during sensing: trimming and adjacent word lines

When applying a programming voltage at one end of a word line of a non-volatile memory circuit, if the word line has a large RC constant the far end of the word line will not rise as fast as the driven end, which can adversely affect device performance. To more quickly raise the voltage on the selected word line, a voltage kick is applied to non-selected word lines, such as dummy word lines, by way of a non-selected sub-block of the selected block. The channel of NAND strings in the non-selected sub-block is used to transfer the kick to the far end of the selected word line of the selected sub-block.

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Sunnyvale, CA, United States of America

Kenneth Louie