Semiconductor memory device and method of performing setting operation in semiconductor memory device

A method of performing a setting operation in a semiconductor memory device, the setting operation being an operation that changes a memory cell from a reset state to a set state, the device comprising:

• a plurality of first lines;
• a plurality of second lines extending to intersect the first lines;
• and
• a plurality of memory cells respectively disposed at intersections of the first lines and the second lines and including a variable resistance element,
• the method comprising:
• applying a setting voltage to a selected memory cell connected to a selected first line and a selected second line;
• comparing a cell current flowing in the selected memory cell during the setting operation and a threshold value current, and determining a time until the cell current reaches the threshold value current;
• and
• executing continuously an additional setting operation that applies the setting voltage to the selected memory cell and changing a voltage application time of the additional setting operation based on the time until the cell current reaches the threshold value current.

A semiconductor memory device, comprising:

• a plurality of first lines;
• a plurality of second lines extending to intersect the first lines;
• a plurality of memory cells respectively disposed at intersections of the first lines and the second lines and including a variable resistance element;
• and
• a control circuit configured to control a voltage applied to the memory cells,
• the control circuit being configured able to, during a setting operation that changes the memory cell to a set state, execute the setting operation such that a setting voltage is applied to a selected memory cell connected to a selected first line and a selected second line, and
• the control circuit being configured able to change a voltage application time of the setting voltage according to a state of change of the selected memory cell during the setting operation, wherein
• the control circuit comprises a current detection circuit configured to compare a cell current flowing in the selected memory cell during the setting operation and a threshold value current, and a timer configured to determine a time until the cell current reaches the threshold value current, and
• the control circuit is configured able to change the voltage application time of the setting voltage based on the time until the cell current reaches the threshold value current.