Patent attributes
In a semiconductor device particularly including a phase change material, the reliability of the read-out operation is improved. In a read-out operation of a phase change memory, a bit line to be read out is precharged in advance with a sufficiently low voltage that can prevent the destructive read operation. In this state, after a word line is activated and a period in which the voltage is sufficiently discharged via a storage element which is in a low resistance state elapses (first read out), charge sharing is performed between the bit line and a read bit line of a sense amplifier which is precharged to a high voltage, and a read-out operation is performed again (second read out). Consequently, the read-out signal amount can be increased while suppressing the read current.
