| 摘要 |
PURPOSE:To erect the triple well structure fit for miniaturization in high noise resistance due to minor carriers without increasing the masking steps while lessening the gap between wells. CONSTITUTION:The title semiconductor device is composed of a buried layer 2 in the opposite conductivity type to that of a p type silicon substrate 1 formed on the whole surface of said substrate 1, the first p type well 3, wall regions 6 in the opposite conductivity type to that of the substrate 1 encircling the periphery of the first p well 3 continuously formed from the buried layer 2 to the surface of the substrate 1, the second p well 4 and the third n well 5 from the surface of the substrate 1 to the inside while the third n well 5 is to be brought into contact with the buried layer 2. |
