| 摘要 |
PROBLEM TO BE SOLVED: To obtain a semiconductor device which can reduce the space factor while enabling a core section formed in a logic circuit to operate at high-speed and, in addition, can prevent the punch-through of the region below an element isolating region of a CMOS. SOLUTION: A resist 4 having an opening 4a on the n-type MOS region 101 side of an element isolating film 3a is formed. In the resist 4, an opening 4b is formed on an n-type MOS region 103 side and the area 103 side of an element isolating film 3b. Then a p-type well 5a is formed under the region matching the opening section 4a of the element isolating film 3a in a core section and, at the same time, a p-type well 5b which is deeper than the element isolating film 3b is formed in a p-type epitaxial layer 2 in a SRAM section. In addition, a p-type channel 6 is formed at the intermediate depth of the p-type well 5b by implanting B+ ions into the epitaxial layer 2 by using the resist 4 as a mask. |
