| 摘要 |
<p>On a semiconductor substrate (101) is formed an epitaxial layer (102) of the conductive type opposite to that of the substrate. In the epitaxial layer (102) is formed an impurity diffused layer (103) of the same conductive type as that of the substrate that is so deep as to reach the semiconductor substrate. CMOS elements and functional elements are formed on the deep impurity diffused layer and on epitaxial layers (110, 111) surrounded by the deep impurity diffused layer. Further, in other epitaxial layers that are electrically isolated are formed impurity diffused layers (106, 108) that do not reach the semiconductor substrate, and CMOS elements and functional elements are formed thereon. This makes it possible to prevent the development of defective writing of EPROM formed on the same semiconductor substrate and to prevent the characteristics from being deteriorated by the back bias of analog circuits.</p> |
