A nonvolatile memory device is provided. A nonvolatile memory device comprises a word line, a bit line, a memory cell array including a first memory cell at an intersection region between the word line and the bit line, a word line voltage generating circuitry configured to generate a program voltage, the program voltage to be provided to the word line, a row decoder circuitry configured to receive the program voltage from the word line voltage generating circuitry and configured to provide the program voltage to the word line, a verification circuitry configured to generate a verification signal in response to verifying a success or a failure of programming of the first memory cell, and a control circuitry configured to apply the program voltage to the first memory cell in response to the verification signal, and configured to cut off the program voltage in response to the verification signal.

A non-volatile storage system includes a mechanism to compensate for over programming during the programming process. That is, after the programming process starts for a set of data and target memory cells, and prior to the programming process completing for the set of data and the target memory cells, the system determines whether a first group of the memory cells has more than a threshold number of over programmed memory cells. If so, then the system adjusts programming of a second group of memory cells to reduce the number of programming errors.

A memory system includes a plurality of memory cells, and the memory cells are multiple-level cells. The memory system performs program operations to program the memory cells. After each program operation, at least one threshold voltage test is performed to determine if threshold voltages of the memory cells are greater than the verification voltage. When the threshold voltage of a first memory cell is determined to be greater than a first verification voltage, the first memory cell will be inhibited from being programmed during the next program operation. When the threshold voltage of a second memory cell is determined to newly become greater than a second verification voltage, where the second verification voltage is greater than the first verification voltage, the second memory cell will be programmed again during the next program operation.

A One Time Programmable (OTP) memory, includes: a first driver coupled to a reference cell by a first bit line; a second driver coupled to an OTP cell by a second bit line; and a comparator having a first input coupled to the first bit line and the reference cell, a second input coupled to the second bit line and the OTP cell, and an output coupled to a logic circuit configured to control the first driver and the second driver.

A One Time Programmable (OTP) memory, includes: a first driver coupled to a reference cell by a first bit line; a second driver coupled to an OTP cell by a second bit line; and a comparator having a first input coupled to the first bit line and the reference cell, a second input coupled to the second bit line and the OTP cell, and an output coupled to a logic circuit configured to control the first driver and the second driver.

A memory controller optimizes read threshold values for a memory device using multi-dimensional search. The controller performs a read operation on cells using a pair of default read threshold values on a multi-dimensional plane. When the read operation has failed, the controller determines program states of cells and a pair of next read threshold values based on the program states and performs an additional read operation using the next read threshold values.

Non-volatile memory cells are programmed by applying a programming signal as a series of programming voltage pulses (or other doses of programming) to selected memory cells and verifying the memory cells between programming voltage pulses. To achieve tighter threshold voltage distributions, a coarse/fine programming process is used that includes a two step verification between programming voltage pulses comprising an intermediate verify condition and a final verify condition. Memory cells being programmed that have reached the intermediate verify condition are slowed down for further programming. Memory cells being programmed that have reached the final verify condition are inhibited from further programming. To reduce the number of verify operations performed, a system is proposed for skipping verification at the intermediate verify condition for some programming voltage pulses and skipping verification at the final verify condition for some programming voltage pulses.

A semiconductor storage device includes memory cells a controller performing a write operation on the memory cells. The write operation includes program loops with a program operation and a verification operation. In a first loop the controller applies a first program voltage and a first verification voltage. Next, a detection operation counts the memory cells with a threshold voltage above a first threshold value. In a second program loop, after the detection operation, the controller applies a second program voltage and a second verification voltage. The values of used for second program voltage and the second verification voltage are set dependent on the counted number of memory cells with a threshold voltage above the first threshold value.

A nonvolatile memory device is provided. A nonvolatile memory device comprises a word line, a bit line, a memory cell array including a first memory cell at an intersection region between the word line and the bit line, a word line voltage generating circuitry configured to generate a program voltage, the program voltage to be provided to the word line, a row decoder circuitry configured to receive the program voltage from the word line voltage generating circuitry and configured to provide the program voltage to the word line, a verification circuitry configured to generate a verification signal in response to verifying a success or a failure of programming of the first memory cell, and a control circuitry configured to apply the program voltage to the first memory cell in response to the verification signal, and configured to cut off the program voltage in response to the verification signal.

According to one embodiment, a semiconductor memory device includes the following configuration. A second word line is provided above a first word line on a substrate. A third word line is provided above the second word line. A semiconductor layer includes a first part that passes through the first word line, a second part that passes through the second and the third word lines, and is provided above the first part, and a joint provided between the first and second parts. When a write operation is performed on a memory cell of the third word line, prior to applying a write voltage to the third word line, a first voltage is applied to a bit line, a second voltage is applied to the third word line, and a third voltage higher than the second voltage is applied to the second word line.