Memory device and operating method thereof

A memory device, comprising:

• a first cell including a first transistor and a capacitor connected to the first transistor, the capacitor storing a voltage corresponding to data;
• a second cell including a second transistor;
• a condition control component configured to apply a stress condition to the second cell;
• a measuring circuit connected to the second cell, the measuring circuit configured to measure a current and/or a voltage output from the second cell;
• and
• a monitoring circuit connected to the measuring circuit, the monitoring circuit configured to:
• calculate a first threshold voltage of the second transistor before the stress condition is applied;
• control the condition control component to apply the stress condition to the second cell;
• calculate a second threshold voltage of the second transistor after the stress condition is applied;
• and
• determine a degree of degradation of the second transistor based on a comparison between the first threshold voltage and the second threshold voltage.

A method of operating a memory device, the method comprising:

• calculating a first threshold voltage of a dummy cell transistor in a dummy cell array;
• applying a stress condition to the dummy cell transistor;
• calculating a second threshold voltage of the dummy cell transistor after applying the stress condition;
• comparing the first threshold voltage and the second threshold voltage;
• and
• measuring a degree of degradation of the dummy cell transistor based on the comparison.

A memory system, comprising:

• a memory device including a memory cell array and a dummy cell array;
• and
• a memory controller configured to control the memory device, wherein the memory device comprises:
• a monitoring circuit configured to:
• determine a first threshold voltage of a dummy cell in the dummy cell array;
• apply a stress condition to the dummy cell;
• determine a second threshold voltage of the dummy cell after applying the stress condition;
• and
• calculate a degradation value of the dummy cell based on a difference between the first threshold voltage and the second threshold voltage.