| 摘要 |
PROBLEM TO BE SOLVED: To solve such a problem that it is difficult to actually establish high density of charge by introducing lanthanoids into HfO<SB>2</SB>, ZrO<SB>2</SB>and TiO<SB>2</SB>because charge accumulation quantity is insufficient and the degree of threshold voltage change cannot be made large in the conventional MONOS wherein charge is accumulated in SiN. SOLUTION: Metal oxides such as Ti oxide, Zr oxide, Hf oxide, etc. that are higher in dielectric ratio than a silicon nitride film are used as a base material, and a multivalent substance of valency of 2 or more (VI valency) is added at appropriate quantity to establish trap level enough to put in/take out atoms into/from the base material. The nonvolatile semiconductor memory has such a charge accumulation layer. COPYRIGHT: (C)2008,JPO&INPIT
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