Patent ID: 11948642
Assignee: KIOXIA CORPORATION
Field: Computer technology (Electrical engineering)
Classification: CPC G | IPC G

Claim 0:
1. A method of controlling a semiconductor memory device,
the semiconductor memory device comprising:
a first memory string including a plurality of first memory cell transistors connected to each other in series;
a plurality of word lines connected to the plurality of first memory cell transistors, respectively;
a first select transistor connected to one end of the first memory string;
a first gate line connected to the first select transistor;
a second select transistor connected to another end of the first memory string;
a second gate line connected to the second select transistor;
a bit line connected to the first select transistor;
a source line connected to the second select transistor; and
a control circuit configured to execute a plurality of write operations for writing data to the plurality of first memory cell transistors and a program operation including a plurality of verify operations, wherein
when,
among the plurality of first memory cell transistors, a memory cell transistor that is a target to write data is a first write target transistor,
among the plurality of word lines, a word line to be connected to the first write target transistor is a select word line, and
among the plurality of word lines, word lines other than the select word line are non-select word lines, and
at completion of the program operation to write data to the first write target transistor:
the controlling circuit is configured to:
apply a voltage to turn on the first select transistor to the first gate line,
apply a voltage to turn on the second select transistor to the second gate line, and
apply a predetermined first voltage higher than a ground voltage to the select word line and the non-select word lines; and

subsequent to the completion of the program operation:
apply a voltage to turn off the first select transistor to the first gate line,
apply a voltage to turn off the second select transistor to the second gate line, and
apply a predetermined second voltage higher than the ground voltage to the select word line and the non-select word lines, wherein the voltage applied to the select word line and the non-select word lines is equal to or greater than the second voltage from a time of the completion of the program operation to a time subsequent to the completion of the program operation.