Abstract: An insulating substrate for mounting semiconductor devices that is composed of a thin flat plate of inexpensive alumina (Al.sub.2 O.sub.3) preferably in the range of 0.26 to 0.29 mm in thickness. Copper foil sheets are applied to both sides of the flat plate with edges spaced a distance back from the end surface of the plate to increase air path distance between the edges of the sheets of foil applied to opposite sides of the plate. The difference in distance between the end surface of the alumina plate and the edges of each copper foil is 0.5 mm or less to balance thermal stress upon heating and cooling of semiconductors soldered to the copper foil.

Abstract: A semiconductor device using an insulation coated metal substrate includes semiconductor elements supported on an insulation coated metal substrate which is made of a metal substrate and an insulation layer disposed on the metal substrate, a wiring of a metallic foil formed on the insulation layer and connected to the semiconductor elements, an insulative sealing material covering the semiconductor elements and the wiring, and a solid insulation with a larger specific inductive capacity than that of the sealing material which is interposed between an edge part of the wiring and the sealing material.

Abstract: A solar cell device in which short-circuiting between a connecting portion of a metal electrode and a transparent electrode of each cell unit is prevented. A plurality of cell units are formed by laminating a transparent electrode, an amorphous silicon layer and a metal electrode disposed on a common transparent substrate, with each two adjacent cell units being connected by an extension of the metal electrode which traverses an edge of the amorphous silicon layer of the cell unit and contacts the exposed extension of the transparent electrode of the adjacent unit. The edge of the amorphous silicon layer traversed by the extension of the metal electrode projects beyond the transparent electrode by a distance significantly greater than the distance between the edges of the amorphous silicon layer and the transparent electrode in the main portion of the cell unit.

Abstract: A solar cell array is equipped with serially or parallel connected reverse polarity diodes formed simultaneously with the array. The diodes are constituted by one or more solar cells of the array which may be shaded to prevent photoelectric conversion, and which are electrically connected in reverse polarity with respect to the remaining cells.