PURPOSE: To improve the performance of both of the undermentioned two elements by compatibility with each other by a method wherein the impurity concentration of the region for forming an active element for small signal formed together with an active element of high withstand voltage is selectively reduced with an impurity of reverse conductivity type.

CONSTITUTION: The regions a1∼a3 having grooves by anisotropic etching are selectively provided with n- layers 16, and an n-layer 20 is superposed and covered with an SiO2 mask M. An n type and a p type impurity are successively implanted 18 to the regions a2 and a3 and then heattreated, resulting in a decrease in the n-concentration of the surface of the layer 20; thereby enabling the formation of a Schottky barrier diode made of metal silicide, and thus keeping the depth conductivity better. The regions are separated from each other by means of p+ layer, n+ layers 15 being led out through p+ layers 24, and a p layer 30 and an n+ layer 32 being then provided as required. Thus, the n type impurity concentration of the epitaxial layer 20 is kept low in the region a1 and selectively high in an n-p-n element Q1 and the other region by the settlement of a recess groove; accordingly the parasitic resistance is reduced and the hFE is increased. The n-p-n elements Q2 and Q3 with built-in Schottky diodes 40 can be formed in the region a2 by series providing with n+ layers 23, a lateral n-p-n element Q4 in the region a3, and complementary elements Q5 and Q6 in the region a4 by coexistence.