Abstract: The electrical performance of a dielectric film for capacitive coupling in an integrated structure is enhanced by forming the polycrystalline electrically conductive layer coupled with the dielectric film substantially unigranular over the coupling area, commonly to be defined by patterning the stacked dielectric and conductive layers. The process forms a polycrystalline silicon film having exceptionally large grains of a size on the same order of magnitude as the dimensions of the patterned details. These exceptionally large grains are obtained by preventing the formation of “precursor nuclei” of subsequent grain formation and growth at the deposition interface with the dielectric that are apparently formed during the first instants of silicon CVD deposition and by successively growing the crystallites at a sufficiently low annealing temperature.

Abstract: The breakdown voltage of a VDMOS transistor is markedly increased without depressing other electrical characteristics of the device by tying the potential of a field-isolation diffusion, formed under the edge portion of a strip of field oxide separating a matrix of source cells from a drain diffusion, to the source potential of the transistor. This may be achieved by extending a body region of a peripheral source cell every given number of peripheral cells facing the strip of field-isolation structure until it intersects said field-isolation diffusion. By so connecting one peripheral source cell every given number of cells, the actual decrement of the overall channel width of the integrated transistor is negligible, thus leaving unaltered the electrical characteristics of the power transistor.