Patent ID: 9142313
Filing Date: 2015-09-22
Classification: G11C

Abstract:
1. A method of operating a nonvolatile memory device in which a plurality of strings are connected to a bit line, each string including at least one string selection transistor, a plurality of memory cells, and at least one ground selection transistor formed in a direction perpendicular to a substrate, the nonvolatile memory device configured to select a pre-pulse mode and a non pre-pulse mode, the method comprising: determining whether an operation mode of the nonvolatile memory device is the pre-pulse mode or the non pre-pulse mode, wherein a result of the determining is different between a read operation and a program verification operation; when the operation mode is the pre-pulse mode, applying a pre-pulse having a particular level to a string selection line connected to a gate of a string selection transistor of at least one unselected string of the plurality of strings for a particular time period, and then performing the read operation or the program verification operation for at least one memory cell of the plurality of memory cells; and when the operation mode is the non pre-pulse mode, performing the read operation or the program verification operation for the at least one memory cell of the plurality of memory cells without applying the pre-pulse to the at least one string selection line.