Disclosed is an operation method of a memory device that includes a memory block including a plurality of cell transistors stacked in a direction perpendicular to a substrate. The plurality of cell transistors may include a ground selection transistor and an erase control transistor. The erase control transistor may be between the substrate and the ground selection transistor. The operation method may include performing a first erase operation on the ground selection transistor, performing a first program operation on the erase control transistor after the first erase operation, performing a second program operation on the ground selection transistor after the first program operation, and performing a second erase operation on the erase control transistor after the second program operation.

A semiconductor memory apparatus including a memory cell array, a switch circuit, and a sensing circuit is provided. The memory cell array includes multiple memory cells. The switch circuit includes at least one switch. Each of the switch receives a control signal and is turned on or off under control of the control signal. When an erase verification is performed, the sensing circuit sequentially receives an erase verification current generated by each of the memory cells through the switch circuit to verify an erase state of the each of the memory cells.

Non-volatile memory systems are disclosed. The memory systems include rows of memory holes FC-SGD and SC-SGD, the latter of which may be created by a SHE cutting operation. The SC-SGD include erase speeds slower than those of FC-SGD. In order to overcome the erase speed disparities, SC-SGD are programmed to a higher Vt as compared to FC-SGD. By programming SC-SGD to a higher Vt, the erase speed increases and matches the erase speed of FC-SGD. Further, different SC-SGDs are cut to different amounts, creating different erase speeds among SC-SGD. SC-SGDs with a greater degree/amount of cut have slower erase speeds as compared to SC-SGDs with a lesser degree/amount of cut. However, verify levels among SC-SGDs can differ to produce SC-SGDs with Vt's such that their erase speeds match with each other as well as with FC-SGD.

Described are systems and methods for performing partial block erase operations. An example memory device comprises: a memory array comprising a plurality of memory cells electrically coupled to a plurality of wordlines; and a controller coupled to the memory array, the controller to perform operations comprising: identifying, in a memory device, a block comprising a plurality of memory cells; estimating, in the block, a number of pages having a predefined program state; determining, based on the number of pages having the predefined program state, an erase verify voltage to be applied to the block; causing an erase operation to be performed with respect to the block; and causing an erase verify operation to be performed, using the erase verify voltage, with respect to the block.

A method for detecting a “slow to erase” condition of a non-volatile memory structure, wherein the method comprises initiating an erase/verify memory operation with respect to the memory structure, wherein the erase/verify memory operation comprises applying an erase verify voltage according to an alternating word line scheme; following the erase/verify memory operation, determining if a first bit scan mode criteria is satisfied; and, if the first bit scan mode criteria is satisfied, initiating a read/verify memory operation wherein, the read/verify memory operation comprises applying a read-pass voltage according to an all word line scheme, and a magnitude of the read-pass voltage is greater than a magnitude of the erase verify voltage. Following the read/verify memory operation, the method also comprises determining if a second bit scan mode criteria is satisfied and, if the criteria is not satisfied, designating the memory structure with a fail status.

A semiconductor memory device includes first conductive layers, second conductive layers, a first semiconductor layer, a charge storage layer, and a first wiring. The semiconductor memory device is configured to execute an erase operation including a first and a second erase loop. In the first erase loop, the semiconductor memory device applies a first voltage to at least a part of the first conductive layers and at least a part of the second conductive layers and applies an erase voltage larger than the first voltage to the first wiring. In the second erase loop, the semiconductor memory device applies the first voltage to at least a part of the first conductive layers, applies a second voltage larger than the first voltage to at least apart of the second conductive layers, and applies the erase voltage to the first wiring.

A semiconductor memory device according to an embodiment includes a plurality of planes including a plurality of blocks each being a set of memory cells, and a sequencer configured to execute a first operation, and a second operation shorter than the first operation. Upon receiving a first command set that instructs execution of the first operation, the sequencer is configured to execute the first operation. Upon receiving a second command set that instructs execution of the second operation while the first operation is being executed, the sequencer is configured to suspend the first operation and execute the second operation or execute the second operation in parallel with the first operation, based on an address of a block that is a target of the first operation and an address of a block that is a target of the second operation.

A memory apparatus and method of operation are provided. The apparatus includes memory cells connected to one of a plurality of word lines and arranged in strings and configured to retain a threshold voltage corresponding to one of a plurality of memory states. A control circuit is coupled to the plurality of word lines and strings and is configured to erase the memory cells using a stripe erase operation in response to determining a cycle count is less than a predetermined cycle count maximum threshold. The control circuit is also configured to perform a dummy cycle operation in response to determining the cycle count is not less than the predetermined cycle count maximum threshold.

A method for dynamically adjusting an erase voltage level to be applied in a subsequent erase cycle, comprising: in a current erase cycle, initiating a current erase/verify loop by applying an initial stored erase voltage level according to an erase sequence in which each successive erase/verify loop is incremented by a pre-determined voltage amount, storing an erase/verify loop count, and determining whether the current erase cycle is complete according to a pass criterion. If the erase cycle is complete, a determination is made as to whether the stored erase/verify loop count equals a pre-defined threshold count. Further, if the stored count does not equal the pre-defined threshold count, the initial stored erase voltage level is adjusted such that, upon applying the adjusted erase voltage level in a subsequent erase cycle, an erase/verify loop count will now equal the pre-defined threshold count.

An operation method of a nonvolatile memory device which includes a memory block having wordlines includes performing an erase on the memory block, performing a block verification on the memory block by using a 0-th erase verification voltage, performing a delta verification on the memory block by using a first erase verification voltage different from the 0-th erase verification voltage when a result of the block verification indicates a pass, and outputting information about an erase result of the memory block based on the result of the block verification or a result of the delta verification. The delta verification includes generating delta counting values respectively corresponding to wordline groups by using the first erase verification voltage, generating a delta value based on the delta counting values, and comparing the delta value and a first reference value.