PURPOSE: To omit a patterning process for a resist film, and to improve the degree of integration of an integrated circuit by also forming an oxide film in a Schottky-barrier-diode formation prearranged region, using the oxide film as a mask in an impurity diffusion for forming a base region and removing the oxide film when boring an electrode window.

CONSTITUTION: A nitride film is patterned so that an oxide film with large film thickness is also formed in an SBD formation prearranged region and the SBD formation prearranged region is not covered. Nitride films 4a, 4b, 4c are each left in an isolation layer and regions into which a collector and a base must be shaped in the patterning of the nitride film 4, but the nitride film is not left in the SBD formation region. Thick SiO2 films 5 are formed through a normal thermal oxidation method. An SiO2 film 5d can be removed through dry etching on the boring of an electrode window.