| 摘要 |
PROBLEM TO BE SOLVED: To provide a phase change memory storing multi-value information and being easy for write-in and read-out. SOLUTION: A memory 11 is provided with a first recording layer 3 and a second recording layer 5 for recording information by causing reversible phase change between a crystal phase and an amorphous phase caused by rise of temperature owing to applying a current pulse. The relation between crystallizing temperature Tx1 of the first recording layer 3 and crystallizing temperature Tx2 of the second recording layer 5 is Tx1<Tx2, and the relation between crystallizing time tx1 of the first recording layer 3 and crystallizing time tx2 of the second recording layer 5 is tx1<tx2. If a resistance value when the first recording layer 3 is an amorphous material phase is assumed to Ra1, a resistance value when the first recording layer 3 is a crystal phase is assumed to Rc1, a resistance value when the second recording layer 5 is an amorphous material phase is assumed to Ra2, and a resistance value when the second recording layer 5 is a crystal phase is assumed to Rc2, Ra1+Ra2, Ra1+Rc2, Ra2+Rc1, Rc1+Rc2 are different one another. |
