Memory device for performing program operation according to incremental step pulse programming method, storage device including the same, and operating method of the memory device

A storage device comprising:

• a memory controller configured to control a memory device to perform a program operation, corresponding to a write request, when the write request is received from a host;
• and
• the memory device including a plurality of memory cells, the memory device performing the program operation by performing a plurality of program loops each including a program voltage apply operation of applying a program voltage to selected memory cells, among the plurality of memory cells, and a verify operation of verifying a program state of the selected memory cells,
• wherein the program loops are determined as program loops in a first state or a second state, based on when a verify operation on a program state having a highest threshold voltage is performed,
• wherein program voltages applied in the first state increase in a step-wise manner by a first step voltage,
• wherein program voltages applied in the second state increase in a step-wise manner by a second step voltage that is lower than the first step voltage, and
• wherein the program loops in the second state are performed after the program loops in the first state.

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

• applying a first program voltage of a first program loop to selected memory cells, among a plurality of memory cells, the first program voltage increasing by a first step voltage as compared with a previous program voltage of a previous program loop;
• performing a verify operation of verifying at least some of a plurality of program states of the selected memory cells;
• and
• applying a second program voltage to the selected memory cells, among the plurality of memory cells, the second program voltage increasing by a second step voltage as compared with the first program voltage of the first program loop, based on when a verify operation on a program state having a highest threshold voltage, among the plurality of program states is performed,
• wherein the second step voltage is lower than the first step voltage.