Storage device and operating method thereof

Abstract

A memory controller having improved wear-leveling performance controls a memory device including a plurality of memory blocks. The memory controller includes a read operation controller, a cell state determiner, and a read reclaim controller. The read operation controller controls the memory device to read selected memory cells of a first block among the plurality of memory blocks by using at least one reference voltage. The cell state determiner compares a number of memory cells among the selected memory cells that are read as first memory cell with a reference number corresponding to the at least one reference voltage, and generates cell state information indicating a memory cell degradation degree corresponding to at least one state. The read claim controller controls the memory device to copy data stored in the first block to a second block, based on a comparison between the memory cell degradation degree with a threshold degradation degree.