Abstract: A semiconductor device includes a semiconductor substrate of a first conductivity type which has a first surface. A first device region formed in the semiconductor substrate has the first conductivity type and a lateral extent that is less than the lateral extent of the first surface of the semiconductor substrate. The first device region is electrically separated from the semiconductor substrate by an isolation structure. The isolation structure includes a buried layer which is doped with a second conductivity type that opposes the first conductivity type and further includes a first elongate sinker of the second conductivity type. The first elongate sinker extends from the first surface into the semiconductor substrate and is in electrical contact with the buried layer. The semiconductor device further includes a breakdown voltage influencing structure of the second conductivity type that is arranged in the semiconductor substrate and laterally adjacent the buried layer.

Abstract: A method of manufacturing a semiconductor device is described. The method includes forming a hard mask over a semiconductor substrate. The hard mask is patterned to generate openings in the hard mask. Deep trenches are formed in the semiconductor substrate by etching through the openings in the hard mask. The openings in the hard mask are widened. A pre-filler side wall layer is formed over the widened openings of the hard mask and the side walls of the deep trenches. The pre-filler side wall layer is recessed down to at least a first depth in the semiconductor substrate. The deep trenches are filled with a filler material. A corresponding semiconductor device is also described.