| 摘要 |
PURPOSE:To contrive to improve the write efficiency by enhancing the injection efficiency of hot electrons by enlarging a channel width on the drain side. CONSTITUTION:A drain region 8 and a source region 9 are formed on one main surface part of a semiconductor substrate, and a channel part 10a is formed between the region 8 and the region 9. On this part 10a, a floating gate 4 is provided by insulation from the substrate, and a control gate 5 by insulation from the gate 4. In this constitution, the width of the part 10a on the drain 8 side is more enlarged than that of the other part. Thereby, a part of the hot electrons generated by an avalanche breakdown in a depletion region close to the drain 8 is injected to the gate 4 by the electric field the gate 5 forms and is then accumulated, but the injection efficiency increases by enlargement of the channel width on the drain 8 side. Therefore, the write time is shortened, and then the write efficiency can be improved. |
