SEMICONDUCTOR MEMORY DEVICE AND OPERATING METHOD THEREOF

摘要

PURPOSE: A semiconductor memory device and an operating method thereof are provided to change erasure bias used for an erasure operation by increasing a program erasure cycle, thereby improving the reliability of the erasure operation. CONSTITUTION: It is determined that a program erasure cycle is reached to one of log scale values which are increased in units of a certain size (S10). Erasure bias used for an erasure operation is changed when the program erasure cycle is reached to one of the log scale values (S20). [Reference numerals] (AA) Start; (BB) No; (CC) Yes; (DD) End; (S10) Is a program cycle reached to one of log scale values which are increased in units of a certain size?; (S20) Change erasure bias