Abstract: A semiconductor device is manufactured by forming an epitaxial layer (22) insulated from a silicon substrate (2), and forming a device in the epitaxial layer (22). On the semiconductor substrate (2), a silicon dioxide layer (4) is formed (FIG. 2A). Then the silicon dioxide layer (4) is provided with openings (14) (FIG. 2D). Silicon carbide is grown until it protrudes from the openings (14) to thereby form a silicon carbide seed crystal layer (16) (FIG. 2E). Next, oxidation is carried out, allowing a field oxide layer (20) to be bonded at the portion under the openings (14) and the silicon carbide seed crystal layer (16) to be insulated from the silicon substrate (2). Thereafter, epitaxial growth is effected from the silicon carbide seed crystal layer (16), thus obtaining an epitaxially grown layers (22). The device is formed in this epitaxially grown layer (22).

Abstract: A semiconductor device and a method of manufacture thereof by which circuit elements are readily formed as a three-dimensional structure without increasing the device size are provided. An N.sup.31 type epitaxially grown layer (4) is first formed on a P.sup.30 type silicon substrate (2), and then a P.sup.30 type diffusion layer (31), an emitter layer (32) (P.sup.30 type) and an N.sup.30 type diffusion layer (33) are formed in the N.sup.31 type epitaxially grown layer (4). Next, an underside of the substrate (2) is etched to form a bottom recessed part (6), from which a collector region (8) (P.sup.+ type) is formed in such a manner that it reaches the P.sup.+ type diffusion layer (31). Thus, a vertical PNP type transistor is obtained readily. In this method, the collector region (8) is formed at a latter step, so that redistribution of the collector region (8) due to epitaxial growth can be avoided.