Composite type semiconductor device having electric isolation layer.

摘要

According to a composite type semiconductor device of the present invention, a buried layer (10) of a second conductive type opposite to the first conductivity type is formed in a region under a major surface of a semiconductor substrate 1 of a first conductivity type, and a conductive layer (11) in which a well region or the like is formed is formed on the buried layer (10). Trench grooves (6) extending into the semiconductor substrate (1) from a surface of the conductive layer (11) through the buried layer (10) are formed, and an insulating film (7b) is formed on side and bottom surfaces of each groove. Poly-silicon (7a) is filled in the grooves to form isolation layers (7) each made of the insulating film (7b) and the poly-silicon (7a). The conductive layer (11) and the buried layer (10) are divided into islands by the isolation layers (7). On these regions, a charge coupled device region (4) having a bipolar transistor, a bipolar element region (5), and element regions (2 and 3) of a MOS structure are formed in a CMOS structure. This composite type semiconductor device can be stably driven with a voltage of 5 V.