| 摘要 |
PURPOSE:To increase the writing erasing frequency of information electric charge, and obtain a flash memory of low voltage or low consumption power, by specifying the relation of thicknesses and specific dielectric constant of a first insulating film and a second insulating film laminated on a semiconductor substrate. CONSTITUTION:A first insulating film 3 composed of, e.g. silicon oxide, silicon nitride, etc., is formed on the main surface of a semiconductor substrate 1. A second insulating film 4 composed of, e.g. tantalum pentoxide, strontium titanate, etc., is laminated on the film 3. The thickness and the specific dielectric constant of the first insulating film 3 are t1 and epsilon1, respectively. The thickness and the specific dielectric constant of the second insulating film 4 are t2 and epsilon2, respectively. The relations 20<=epsilon2/epsilon1 and t2/t1<=epsilon2/epsilon1 are satisfied. Thereby the writing erasing time of information electric charge is reduced, so that the writing erasing frequency is increased, and a flash memory of low voltage or low consumption power can be obtained. |
