Memory device and programming method thereof

A programming method of a memory device comprising a multi-level cell, the programming method comprising:

• determining that a resistance of a multi-level cell is less than a lower limit of a target range;
• sequentially applying incremental step reset pulses to the multi-level cell to increase the resistance of the multi-level cell until the resistance of the multi-level cell is in the target range or until the resistance of the multi-level cell is beyond an upper limit of the target range;
• recording a last reset pulse of the incremental step reset pulses applied to the multi-level cell in a look-up table, in response to determining that the resistance of the multi-level cell is beyond the upper limit of the target range;
• determining incremental step set pulses to be applied to the multi-level cell based on the last set pulse in the look-up table;
• and
• sequentially applying the incremental step set pulses to the multi-level cell until the resistance of the multi-level cell is in the target range or until the resistance of the multi-level cell passes the lower limit of the target range.

A memory device, comprising:

• a memory array, comprising a plurality of multi-level cells;
• and
• a memory controller, coupled to the memory array, configured to:
• determine whether a resistance of a multi-level cell is greater than an upper limit of a target range;
• in response to determining that the resistance of the multi-level cell is greater than the upper limit of the target range, sequentially apply incremental step set pulses to the multi-level cell to reduce the resistance of the multi-level cell until the resistance of the multi-level cell is in the target range or until the resistance of the multi-level cell passes a lower limit of the target range;
• record a last set pulse of the incremental step set pulses applied to the multi-level cell in a look-up table, in response to determining that the resistance of the multi-level cell passes the lower limit of the target range;
• determine incremental step reset pulses to be applied to the multi-level cell based on a last reset pulse in the look-up table;
• and
• sequentially apply the incremental step reset pulses to the multi-level cell until the resistance of the multi-level cell is in the target range or until the resistance of the multi-level cell is beyond the upper limit of the target range.