Semiconductor memory device and semiconductor memory system including the same

Abstract

A semiconductor memory device includes a plurality of normal word lines and a plurality of redundancy word lines which are disposed adjacent to the normal word lines, a detection block suitable for detecting a first word line whose active history satisfies a predetermined condition and a second word line adjacent to the first word line as a target word line and a target neighboring word line, among the normal word lines and the redundancy word lines, and a control block suitable for sequentially refreshing the normal word lines and the redundancy word lines whenever a refresh command is applied, and additionally refreshing the target word line, the target neighboring word line and a normal word line adjacent to the redundancy word lines among the normal word lines.