Method of forming structures with buried regions in a semiconductor device

摘要

A monocrystalline silicon substrate is subjected to the following operations: implantation of doping impurities in a high concentration to form a planar region of a first type; selective anisotropic etching in order to hollow out trenches to a depth greater than the depth of the planar region; oxidation of the silicon inside the trenches, starting a certain distance from the surface of the substrate, until a silicon dioxide plaque is formed, surmounted by residues of strongly-doped silicon; epitaxial growth between and on top of the silicon residues to close the trenches and to bring about a redistribution of the doping impurities into the silicon grown to produce a buried region with low resistivity in an epitaxial layer of high resistivity.