| 摘要 |
PURPOSE:To manufacture easily a structure in which an island region having a first conductive type diffusion region formed reaches the substrate of the first conductive type, by thinning the thickness of an epitaxial layer of a second conductive type MOS circuit device. CONSTITUTION:In the same way as trenches 100 used for inter-layer separating at a bi-olar transistor section 1,000, a trench 100 is also formed at an n-channel MOS transistor section 3,000. At the bottom of the trench 100, a source and drain 9, gate 10 and substrate taking-out region 7 are formed. A p-type island region 20 is formed at the bottom of the trench 100, and the thickness of an n-type epitaxial layer 4 of the n-channel MOS transistor 3,000 is thinner than that of the bi-polar transistor 1,000 and p-channel MOS transistor 2,000 by the depth of the trench. Since diffusion of the p-type island region 20 required to be connected with the p-type substrate 1 may be made shallow, heat treatment necessary for the duffusion can be shortened, swelling toward the surface of the n<+> buried layer at the bi-polar transistor 1,000 can be reduced, and a thinner epitaxial layer can be used, with the result that reduction of the vertical dimension of a device and thus fining the device are made possible. |
