| 摘要 |
PURPOSE:To improve the writing-in characteristics of a memory without widening the width of a common source by a method wherein a high concentration impurity is implanted in a part distant from a channel region in the central part of the common source region. CONSTITUTION:A region 12 in high N-type impurity concentration is formed in the central part of a common source region 8. The high impurity concentration region 12 is formed in the position having no effect on the channel length of a memory transistor. On the other hand, a contact 9 for common ground is provided on said region 12 so that the source resistance of the memory transistor on the position distant from the contact 9 may be reduced satisfactorily. Consequently, the writing-in characteristics of EPROM, etc., can be improved. |
