| 摘要 |
PURPOSE:To stabilize writing process by providing the source region which is enclosed with a higher concentration impurity range of one conductivity type than that of a semiconductor substrate and, in addition to it, by providing a higher concentration impurity ranges which are in contact with a drain region than that of the semiconductor substrate in a part of a channel region. CONSTITUTION:In a nonvolatile memory semiconductor device which has a memory medium zone for accumulation of electric charge under a gate electrode, an N type source region 23 is enclosed with a P<+> high concentration impurity range 11. In addition to it, the high concentration impurity ranges 20, 21 which are in contact with a drain region 24 are formed by boron-ion implantation into a part of a channel region 17. Nonvolatile semiconductor elements 74, 76 correspond with the channel regions 20, 21 into which high concentration boron- ion has been implanted, and a nonvolatile semiconductor element 75 corresponds with a channel region 23 other than the area into which high concentration boron-ion is implanted. Impurity concentration resulting from high concentration boron-ion implantation allows stabilized high-speed writing by the elements 74, 76. |
