Abstract: A semiconductor device having a planar pn junction (2) between a more highly doped first region (4) and a more weakly doped second region (5) of the opposite conductivity type, a narrow strip-shaped conductive layer (9) used as a field plate being present above this junction (2), which layer has substantially the same potential as the first region (4) and an edge (7) which substantially coincides with the pn junction (2). The conductive layer (9) locally comprises a widened part (14) suitable for contacting purposes, which, in order to avoid breakdown, is constituted by a protuberance of the said edge (7) towards the first region (4). The invention is of particular importance in DMOS transistor structures, in which the said field plate is connected to the gate electrode.

Abstract: By the use of high-ohmic polycrystalline silicon(poly) in MIS elements, a depletion layer can be formed in the poly material which brings about an electric decoupling between the poly (gate) and the underlying semiconductor body. This effect can be utilized advantageously in various circuit elements, such as in CCD's, in order to obtain a favorable potential distribution in the substrate; in MOS transistors in order to reduce the parasitic capacities; and in high-voltage devices in order to increase the breakdown voltage at the edge of the field plate (resurf).

Abstract: A semiconductor device of the "RESURF" type has a substrate region and a superimposed semiconductor layer which forms a p-n junction with the substrate region. The semiconductor layer has an island-shaped region which is depleted at least locally up to the surface at a reverse voltage applied across the p-n junction which is well below the breakdown voltage of the p-n junction. According to the invention the island-shaped part of the semiconductor layer over at least a part of its area has a doping profile in the vertical direction with at least two overlying layer portions with different average net doping concentrations and of the same or opposite conductivity type, so as to increase the current-carrying capacity of the semiconductor layer.

Abstract: A semiconductor device having two PIN-diodes arranged in series and in opposition, in which the semiconductor body comprises two surface zones of a first conductivity type which extend in a high-ohmic surface layer, said surface layer separating the surface zones from one another and from a low-ohmic region of the second conductivity type. The surface zones and the low-ohmic region are contacted at the same surface of the semiconductor body, preferably by means of beam leads. The device is particularly suitable for high frequency applications and may form part of an integrated circuit.