Method of reducing program disturbance in memory device and memory device utilizing same

A memory system, comprising:

• a memory device, comprising:
• memory strings, one of the memory strings comprising memory cells, a select transistor coupled to a bit line and a select line, and a dummy cell coupled to a dummy word line and arranged between the select transistor and the memory cells;
• and
• a peripheral circuit coupled to the memory strings and configured to, in a pre-pulse period of a program operation:
• in a first period, apply a first voltage to the dummy word line to turn on the dummy cell and apply a second voltage to the select line to turn on the select transistor;
• in a second period after the first period, apply a third voltage to the dummy word line to turn off the dummy cell and apply a fourth voltage to the select line, wherein the third voltage is smaller than the fourth voltage;
• and
• in a third period after the second period, apply a fifth voltage to the select line to turn off the select transistor;
• and
• a memory controller coupled to the memory device and configured to control the memory device.

A method of operating a memory device, comprising:

• in a pre-pulse period of a program operation:
• in a first period, applying a first voltage to a dummy word line to turn on a dummy cell and apply a second voltage to a select line to turn on a select transistor, wherein the memory device comprises memory strings, one of the memory strings comprising memory cells, the select transistor coupled to the select line and a bit line, and the dummy cell coupled to the dummy word line and arranged between the select transistor and the memory cells;
• in a second period after the first period, applying a third voltage to the dummy word line to turn off the dummy cell and apply a fourth voltage to the select line, wherein the third voltage is smaller than the fourth voltage;
• and
• in a third period after the second period, applying a fifth voltage to the select line to turn off the select transistor.