Semiconductor memory device and memory system including the same

Abstract

A semiconductor memory device includes a memory cell array, an error correction code (ECC) engine, an error check and scrub (ECS) circuit, a row hammer management circuit and a refresh control circuit. The ECC engine generates an error generation signal based on a result of an ECC decoding. The ECS circuit generates scrubbing addresses and outputs at least one of the scrubbing addresses as an error address based on the error generation signal. The row hammer management circuit stores an error flag with a first logic level in count cells, compares counted values with different reference number of times based on a logic level of the error flag and outputs a hammer address. The refresh control circuit receives the hammer address and performs a hammer refresh operation on one or more victim memory cell rows which are physically adjacent to the memory cell row corresponding to the hammer address.