| 摘要 |
PURPOSE:To prevent a latch-up phenomenon without causing the increase of an area by forming a high-concentration buried layer of the same conduction type as a well region to the semiconductor base body of the bottom of the well region. CONSTITUTION:The boron ion implanted layer 24 of high concentration is formed selectively to the surface of a substrate 21, and an n type silicon layer 25 is grown on the whole surface in an epitaxial manner. Boron ions are implanted from an opening section 27 to selectively form a boron ion implanted layer 28. The p well region 30 being in contact with the upper surface of the p<+> type buried layer 29 is formed through heat treatment in a nitrogen atmosphere. With a CMOS cmanufactured through several processes, density can be increased because the latch-up phenomenon is prevented by the p<+> buried layer, etc. formed in the depth direction of the base body without forming a guard ring region. |
