PURPOSE: To allow the multi-functions and high performance of an IC, by forming a second channel region in an epitaxially layer on one conductive type region formed by the same process as that of a first channel region.

CONSTITUTION: A P well 4 is formed on an N type Si substrate 10 by the implantation and diffusion of B. Next, an oxide film 5 on a region wherein an insulation gate static induction transistor (MOSSIT) is provided is opened, thus a non-single crystal Si thin film 24 is deposited, and accordingly the unnecessary part is removed. Thereafter, it is heat-treated in non-oxidizing atmosphere, the thin film 24 is formed into a single crystal layer 114 by a solid epitaxial growth, and thereat simultneously the crystal layer 114 is turned into P type with lower impurity density by the diffusion from the P well 4. Thereafter, N+ source and drain regions 11, 12 of an MOS transistor (MOST) T1, N+ source and drain regions 111, 112 of an MOSSIT T2 and respective gate oxide films 13, 113 are simultaneously formed, and then the MOST T1 is formed on the P well 4 and the MOSSIT T2 on the single crystal layer 114.