Sandisk Technologies Inc.

Western Digital Technologies, Inc.

Hiroki Yabe

Koichiro Hayashi

Toru Miwa

Takuya Ariki

Naoki Ookuma

Yuki Fujita

Masahito Takehara

Masaaki Higashitani

Ken Oowada

Kiyohiko Sakakibara

Masahiro Kano

Kazuki Yamauchi

Ohwon Kwon

Anirudh Amarnath

Kou Tei

Chia-Kai Chou

Naoto Norizuki

Jongyeon Kim

Jiawei Xu

Keiji Nose

A semiconductor device includes a plurality of memory blocks and a bit-line-bias block. A source-drain erase bias voltage is applied between a source line and a bit lines through the bit-line-bias block during an erase operation.

Three-dimensional memory device including a bit-line-bias vertical transistor block and methods of operating the same

Systems and methods are provided for sensing a data state of a memory cell. In an example implementation, systems and methods disclosed herein perform a method that includes connecting a first sensing node and a second sensing node to a bitline of a sensing amplifier to simultaneously discharge first and second capacitors connected to the first and second sensing nodes, respectively, through the memory cell. After a first sensing period, the second sensing node is disconnected from the bitline, which includes a first voltage level based on discharging the second capacitor. After a second sensing period, the first sensing node is disconnected from the bitline, which includes a second voltage level based on discharging the first capacitor. First and second sensing results are latched based on the first and second voltage levels, respectively, and a data state of the memory cell is based on the first and second voltage levels.

Sense amplifier architecture providing reduced program verification time

Technology is disclosed herein for sensing memory cells while compensating for resistance along an electrical pathway between a voltage driver and a control line connected to the memory cells. A control circuit provides a voltage from the voltage driver over a first electrical pathway to a control line in a first block and a second electrical pathway to a control line in a second block. The control circuit senses first memory cells in the first block and the second memory cells in the second block while compensating for a difference in resistance of the first and second electrical pathways. In one aspect, the control circuit discharges a first sense node for a different period of time than a second sense node to compensate for the difference in resistance. Compensating for the difference in resistance compensates for a different IR drop of the electrical pathways.

IR drop compensation for sensing memory

Technology is disclosed herein for a memory system that regulates charge pump current during a ramp up of the output voltage. The memory systems operates the charge pump in a current regulation mode while the charge pump output voltage ramps up. After the output voltage crosses a threshold voltage, the charge pump is operated in a voltage regulation mode in which the output voltage is regulated to a target output voltage. In one aspect, the memory system generates a random duty cycle clock in the current regulation mode. The memory system determines a target duty cycle for the random duty cycle clock that will regulate the input current of the charge pump to a target current, given the present output voltage. A clock based on the random duty cycle clock is provided to a clock input of the charge pump to regulate the charge pump current.

Charge pump current regulation during voltage ramp

Memory cell sensing by charge sharing between two sense nodes is disclosed. A first sense node and a second sense node are pre-charged and the second node is discharged initiating charge sharing between the first sense node and the second sense node that results in an improved sense margin. Sensing circuitry disclosed herein may include one or more pre-charge circuits, sense enable circuits, and charge-sharing circuits. The increased sense margin achieved by sensing circuitry disclosed herein provides better noise immunity and more accurate sensing results.

Memory cell sensing by charge sharing between sensing nodes

A flash memory die includes (i) a first subset of planes including blocks of flash memory cells connected to a first number of word line layers and a plurality of bit lines having a first length, (ii) a second subset of planes including blocks of flash memory cells connected to a second number of word line layers less than the first number of word line layers and a plurality of bit lines having a second length shorter than the first length, (iii) first peripheral circuitry implemented underneath the first subset of planes and including first sense amplifier circuitry and first peripheral control circuitry connected to the first subset of planes, and second peripheral control circuitry connected to the second subset of planes, and (iv) second peripheral circuitry implemented underneath the second subset of planes and including second sense amplifier circuitry connected to the second subset of planes.

Hetero-plane data storage structures for non-volatile memory

A data storage system includes a storage medium including a plurality of columns of memory cells, a storage controller coupled to the storage medium, and data path circuitry including a data bus coupled to the storage controller, the data bus configured to receive a plurality of bytes of data to be written to the plurality of columns of memory cells; a block of data latches having a pitch equal to a first number of bit lines of the plurality of columns of memory cells; and column redundancy circuitry configured to pass the plurality of bytes of data to the block of data latches via the plurality of columns in accordance with a nonconsecutive mapping scheme. The nonconsecutive mapping scheme includes mapping each group of three bytes to two columns by splitting one byte of each group of three bytes into two nibbles.

Nonconsecutive mapping scheme for data path circuitry in a storage device

A method for programming three page user data in a memory array of a non-volatile memory system, comprising converting each three-bit value data pattern of the user data into a representative pair of two-bit data values, simultaneously programming two single-state memory cells with a first of the pair of representative two-bit data values, wherein the two single-state memory cells are located along a first common word line of two memory cell strings, and simultaneously programming two single-state memory cells with a second of the pair of representative two-bit data values, wherein the two single-state memory cells are located along a second common word line of the two memory cell strings.

Three-valued programming mechanism for non-volatile memory structures

A level shifting circuit includes negative voltage shifting circuitry including a first leg and a second leg. The first leg includes a first NMOS transistor and a first PMOS transistor in series with a first input node and a negative amplified voltage, and the second leg includes a second NMOS transistor and a second PMOS transistor in series with a second input node and the negative amplified voltage. The level shifting circuit further includes positive voltage shifting circuitry including a first plurality of high voltage transistors in series with a positive amplified voltage and an output node of the level shifting circuit, and a second plurality of high voltage transistors in series with a first intermediate node of the first leg of the negative voltage shifting circuitry and the output node of the level shifting circuit. The level shifting circuitry further includes input circuitry including a plurality of inverters.

Level shifter with improved negative voltage capability

Methods for reducing read disturb using NAND strings with poly-silicon channels and p-type doped source lines are described. During a boosted read operation for a selected memory cell transistor in a NAND string, a back-gate bias or bit line voltage may be applied to a bit line connected to the NAND string and a source line voltage greater than the bit line voltage may be applied to a source line connected to the NAND string; with these bias conditions, electrons may be injected from the bit line and annihilated in the source line during the read operation. To avoid leakage currents through NAND strings in non-selected memory blocks, the threshold voltages of source-side select gate transistors of the NAND strings may be set to a negative threshold voltage that has an absolute voltage value greater than the source line voltage applied during the read operation.

Threshold voltage setting with boosting read scheme

A level shifting circuit includes negative voltage shifting circuitry including a first leg and a second leg. The first leg includes a first plurality of NMOS transistors in series with a first input node and a negative amplified voltage, and the second leg includes a second plurality of NMOS transistors in series with a second input node and the negative amplified voltage. The level shifting circuit further includes positive voltage shifting circuitry including a first plurality of high voltage transistors in series with a positive amplified voltage and an output node of the level shifting circuit, and a second plurality of high voltage transistors in series with a first intermediate node of the first leg of the negative voltage shifting circuitry and the output node of the level shifting circuit. The level shifting circuitry further includes input circuitry including a plurality of inverters.

A storage device for verifying whether memory cells have been programmed. The storage device may be configured to use a verification technique, that is part of a set of verification techniques, to verify data states of a set of memory cells of a selected word line. The one or more verification techniques may be utilized based on an iteration of the verify operation that is to be performed. The storage device may be further configured to perform, using the verification technique, a next iteration of the program-verify operation to verify whether one or more memory cells have been programmed. Using the verification technique and performing the next-iteration of the program-verify operation are to be repeated until the set of memory cells have been verified.

Loop-dependent switching between program-verify techniques

A non-volatile memory apparatus is provided and includes a substrate having a major surface extending longitudinally. A stack of first and second sets of word lines and insulating layers extends along and over the major surface longitudinally and alternating with and overlying one another vertically to define a device region. The first and second sets of word lines each respectively extends longitudinally beyond a first and second side of the device region a decreasing longitudinal distance from the device region as a vertical distance from the major surface increases to define first and second stepped contact regions. Word line contacts extend vertically in the first and second stepped contact regions. The second set of word lines in the first stepped contact region do not contact the word line contacts and the first set of word lines in the second stepped contact region do not contact the word line contacts.

Word line architecture for three dimensional NAND flash memory

An apparatus is provided that includes a plurality of NAND strings having a common set of word lines. Each NAND string includes data memory cells for data storage and dummy memory cells connected in series with the data memory cells. A first group of NAND strings includes dummy memory cells with a first pattern of threshold voltages and a second group of NAND strings includes dummy memory cells with a second pattern of threshold voltages for separate isolation of data memory cells of the first and second groups of NAND strings from corresponding bit lines.

Apparatus and methods for configurable bit line isolation in non-volatile memory

A sense amplifier architecture is presented that can reduce sensing times by being able to sense smaller voltage swings between an ON memory cell and an OFF memory cell. The sense amplifier includes a sensing capacitor that, on one side, is connectable to multiple bit lines and, on the other side, to a main sense amplifier section. The main section includes a latch formed of a pair of inverters that has an input connected to the capacitor and an output that is connected to the other side of the capacitor by a third inverter. To pre-charge the latch, the input and output nodes are shorted and then the capacitor is connected to discharge the capacitor through a selected memory cell based on whether it is ON or OFF. A programming data latch for each bit line can bias the bit line to either a program enable or program inhibit level.

Growing community of inventors

Yokohama, Japan

Hiroki Yabe