| 摘要 |
<p>PURPOSE:To reduce the deterioration in frequency characteristics on a high frequency circuit as well as to decrease the lag time on a high speed digital circuit by a method wherein a diffusion region is provided in such a manner that it reaches a substrate penetrating the first and the second epitaxial layers. CONSTITUTION:A P<+> diffusion layer 66 of the same conductive type as a P type substrate 61 is formed. Then, a P<+> diffusion layer 64 and the P<+> diffusion layer 66 are brought in a conductive status by performing an annealing treatment, and a P type isolated layer 67 of the same conductive type as the P type substrate 61 is formed. In this case, the impurity density and the thickness of the second N type epitaxial layer 65 can be determined based on the required characteristics of the element. Then, after an element 68 has been formed in the region of the second epitaxial layer 65, an insulating film 69 is formed, and the insulating film 69 located on the part where the element 68, the P type isolated layer 67 and a wiring layer will be connected is removed. Then, a conductive metal is adhered, and a wiring layer 70 is formed for the purpose of obtaining a desired wiring pattern by performing an etching.</p> |
