Patent ID: 8094485
Filing Date: 2012-01-10
Classification: G11C,H01L

Abstract:
1. A variable resistance nonvolatile storage device comprising: a semiconductor substrate; a nonvolatile storage element including: a first electrode; a second electrode; and a variable resistance layer in which a resistance value reversibly varies based on electrical signals each having a different polarity, said variable resistance layer being interposed between said first and second electrodes and provided in contact with said first and second electrodes, and the electrical signals being applied between said first and second electrodes; and a MOS transistor formed on a main surface of said semiconductor substrate, wherein said variable resistance layer includes an oxygen-deficient oxide of one of tantalum and hafnium, said first and said second electrodes are made of materials of different elements, a standard electrode potential V a drain of said MOS transistor is connected with one of said first and second electrodes of said nonvolatile storage element to form a memory cell so that a substrate bias effect occurring in said MOS transistor when a voltage signal having a polarity which causes a high resistance change in said variable resistance layer is applied to said MOS transistor and said nonvolatile storage element is smaller than a substrate bias effect occurring in said MOS transistor when a voltage signal having a polarity which causes a low resistance change in said variable resistance layer is applied to said MOS transistor and said nonvolatile storage element.