Monolithic silicon integrated semiconductor circuit - where channel stopper zone is formed in base of trench, which is then filled with silica

摘要

A monocrystalline Si substrate (S) of one conductivity type is covered with an epitaxial, monocrystalline Si layer (e) of opposite conductivity. Layer (e) is next partly covered with a silicon nitride mask (N) so a trench can be etched in layer (e). The surface of the trench is then covered by a thin oxide layer (01); and ions of a non-dopant are implanted to form a damaged zone in layer (01). The damaged zone is easily removed by etching, leaving the remainder of layer (01) which is used as a mask for doping to form a channel stopper zone (U). The trench is then filled with oxide (O). As compared with an earlier process (DE2438256), this process does not damage the crystal lattice in the Si adjacent to the trench.