| 摘要 |
<p>PROBLEM TO BE SOLVED: To obtain a flash EEPROM device which can be programmed highly efficiently, can be highly integrated, and can use low power or low programming voltage by respectively forming impurity areas doped with specific conductive impurities in a channel area adjacent to a source area and drain area. SOLUTION: A source region 23 and a drain region 25 of a second conductivity are formed on both sides of a channel near the surface of a semiconductor substrate 21 of a first conductivity. Then a first impurity region 31 of the first conductivity is formed in the channel region adjacent to the source region 23, and a second impurity region 33 of the second conductivity is formed in the channel region adjacent to the drain region 25. In addition, a gate-insulating film, a floating gate 27, an interlayer insulating film, and an adjusting gate 29 are successively formed on the channel region. The impurity concentration in the first impurity 31 is made higher than that in the substrate 21, and the impurity concentration in the second impurity 33 is made lower than that in the source 23 or the drain 25.</p> |
