Nonvolatile memory device, storage device including nonvolatile memory device and reading method of nonvolatile memory device

A nonvolatile memory device, comprising:

• at least one memory block, including at least a first memory block comprising a plurality of cell strings arranged in rows and columns stacked perpendicular to a substrate, wherein the cell strings include:
• SSTs connected to string select lines (SSLs), ground select transistors (GSTs) connected to ground select lines (GSLs), a plurality of nonvolatile memory cells connected to word lines, and first and second dummy memory cells connected to first and second dummy word lines;
• and
• a row decoder circuit configured to apply voltage waveforms to the SSLs, GSLs, word lines, and first and second dummy word line during a data read operation, including:
• applying a string line select voltage to a selected SSL for selected cell strings to turn on the SSTs of the selected cell strings,
• applying a ground line select voltage to a selected GSL for selected cell strings to turn on the GSTs of the selected cell strings,
• applying a read pass voltage to unselected word lines of unselected nonvolatile memory cells to turn on the unselected nonvolatile memory cells of the selected cell strings,
• applying a read select voltage to a selected word line of selected nonvolatile memory cells to read data from the selected nonvolatile memory cells,
• applying a SSL prepulse to SSLs of unselected cell strings, and then applying an unselected SSL voltage to turn off the SSTs of the unselected cell strings;
• applying a GSL prepulse to GSLs of unselected cell strings, and then applying an unselected GSL voltage to turn off the GSTs of the unselected cell strings;
• applying a first dummy word line prepulse to the first dummy word line such that the first dummy memory cells are turned on and then turned off, and subsequently applying a first dummy word line voltage to the first dummy word line to turn on the first dummy cells again;
• and
• applying a second dummy word line prepulse to the second dummy word line such that the second dummy memory cells are turned on and then turned off, and subsequently applying a first dummy word line voltage to the first dummy word line to turn on the first dummy cells again,
• wherein the row decoder circuit is further configured to apply positive recovery voltages to the word lines and first and second dummy word lines at an end of the data read operation.

A method of performing a data operation for a nonvolatile memory device comprising:

• at least one memory block, the memory block comprising a plurality of cell strings arranged in rows and columns stacked perpendicular to a substrate, wherein the cell strings include:
• string select transistors (SSTs) connected to string select lines (SSLs), ground select transistors (GSTs) connected to ground select lines (GSLs), a plurality of nonvolatile memory cells connected to word lines, and first and second dummy memory cells connected to first and second dummy word lines, the method comprising:
• applying a string line select voltage to a selected SSL for selected cell strings to turn on the SSTs of the selected cell strings;
• applying a ground line select voltage to a selected GSL for selected cell strings to turn on the GSTs of the selected cell strings;
• applying a read pass voltage to unselected word lines of unselected nonvolatile memory cells to turn on the unselected nonvolatile memory cells of the selected cell strings;
• applying a read select voltage to a selected word line of selected nonvolatile memory cells to read data from the selected nonvolatile memory cells;
• applying a SSL prepulse to SSLs of unselected cell strings, and then applying an unselected SSL voltage to turn off the SSTs of the unselected cell strings;
• applying a GSL prepulse to GSLs of unselected cell strings, and then applying an unselected GSL voltage to turn off the GSTs of the unselected cell strings;
• applying a first dummy word line prepulse to the first dummy word line such that the first dummy memory cells are turned on, then turned off, and subsequently applying a first dummy word line voltage to the first dummy word line to turn on the first dummy cells again;
• and
• applying a second dummy word line prepulse to the second dummy word line such that the second dummy memory cells are turned on and then turned off, and subsequently applying a first dummy word line voltage to the first dummy word line to turn on the first dummy cells again.