| 摘要 |
PROBLEM TO BE SOLVED: To provide a semiconductor memory device in which memory holding operation of not less than 2 bits is possible in a single transistor and miniaturization is easily achieved. SOLUTION: A gate insulating film 12 is formed on a semiconductor substrate 11 of a first conductive type, and a gate electrode 13 is formed on the film 12. Charge holding portions 10A, 10B are formed on both sides of the gate electrode 13 respectively, and first and second diffusion-layer regions 17, 18 with a second conductive type are formed on regions of the semiconductor substrate 11 corresponding to the portions 10A, 10B, respectively. The charge holding portions 10A, 10B change the amount of electric current depending on the amount of the charge held in the portions 10A, 10B, the current flowing from one of the regions 17, 18 to the other through a channel region when voltage is applied to the gate electrode 13. A part of the charge holding portions 10A, 10B are situated below an interface between the gate insulating film 12 and the channel region. COPYRIGHT: (C)2004,JPO&NCIPI
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