PROGRAMMING METHOD FOR THRESHOLD VOLTAGE-CONTROLLED PHASE-CHANGE RANDOM ACCESS MEMORY

摘要

A programming method of a threshold voltage-controlled PRAM(Phase-change Random Access Memory) is provided to improve reliability of data writing by controlling a threshold voltage efficiently. A program region with a threshold voltage corresponding to high data and low data is formed by determining amorphous state of a chalcogen material through programming. During the programming, the quenching speed of the chalcogen material is controlled by control of trailing edges of program pulses so that a threshold voltage of the chalcogen material is controlled. The programming pulse has a melting duration and a quenching duration, and the quenching duration is changed in correspondence to the program information in order to control a quenching period of the chalcogen material melted in the melting duration.