Memory device and program operation thereof

Abstract

In certain aspects, a memory device includes a first memory string including a first drain, a first drain select gate (DSG) transistor, first memory cells, and a first drain dummy transistor between the first drain and the first DSG transistor. The memory device also includes a first bit line coupled to the first drain, a first drain dummy line coupled to the first drain dummy transistor, a first DSG line coupled to the first DSG transistor, word lines respectively coupled to the first memory cells, and a peripheral circuit configured to perform a program operation on a target memory cell of the first memory cells coupled to a selected word line of the word lines. To perform the program operation, the peripheral circuit includes a bit line driver coupled to the first bit line and configured to apply a first bit line voltage to select the first bit line, and a word line driver coupled to the first drain dummy line and the first DSG line and configured to apply a DSG voltage to the first DSG line to turn on the first DSG transistor, and apply a drain dummy line voltage to the first drain dummy line to turn on the first drain dummy transistor. The drain dummy line voltage is greater than the DSG voltage.