PURPOSE: To form an MIS type capacity element on the same semiconductor substrate as an MIS type field effect transistor by a method wherein the semiconductor region of a second conductivity type is formed at a part of the surface of the semiconductor substrate of a first conductivity type, and polycrystalline semiconductor layers are formed via an insulation film.

CONSTITUTION: A P type semiconductor region 4 is formed by diffusing boron from the window 3 of the insulation film 2 on an N type semiconductor substrate 1. A window 6 is formed, and then oxide films 7a and 7b are formed by thermal oxidation method and used as the dielectric of a capacity element and the gate oxide film of a field effect transistor. A P type depletion channel layer 9 is formed by implanting boron, a polycrystalline semiconductor layer is formed and selectively removed, and thus window openings and the polycrystalline semiconductor layers 13, 14 are formed. A P+ layer 15, a P type drain region 16 and a P type source region 17 are formed by diffusing boron. An insulation film 18 is formed and selectively removed, resulting in the formation of electrode lead-out contact holes, and then the lead-out electrodes 19a and 19b of an MIS type capacity element 20a and a drain electrode 19c, source electrode 19d and gate electrode 19e of an MIS type field effect transistor 20b are formed.