| 摘要 |
PURPOSE:To improve the high speed and high frequency characteristics of a semiconductor device by increasing the depth of a P type region (in case of N- channel) from the bottom of an N<+> type region as compared with the width of a channel region. CONSTITUTION:Part of an SiO2 film 9 is removed, and phosphorus ions are implanted at 30kV, thereby forming a region 14. At this time it corresponds to the case that the thickness tOX of the film is extremely thin, and the spread of the phosphorus in the lateral direction is short. Accordingly, the length of the main portion of the channel is determined by the superposing width at boron ion implanting time. The depth 15 of the P<+> type region largely affects the resistance of the P<+> type region. When thus formed, the depth 16 of the P<+> type region can be increased as compared with the width 15 of the channel. Accordingly, even if the width 15 of the channel is narrowed, the depth 16 can have a sufficiently large value. Therefore, it becomes an element structure extremely effective for high frequency and high speed. |
