Abstract: A semiconductor device with a bipolar transistor that decreases the parasitic capacitance between a base connection layer and a collector region is provided. This device is comprised of a semiconductor substrate having a main surface, a collector region formed in the substrate, a base region formed in the substrate, an emitter region formed in the substrate, a first dielectric layer formed on the main surface of the substrate to be overlapped with the collector region, a conductive layer formed on the first dielectric layer and applied with a specific electric potential, a second dielectric layer formed to cover the conductive layer, a base connection layer formed on the second dielectric layer and electrically connected to the base region, and a base electrode electrically connected to the base connection layer. The emitter region, the base region, and the collector region constitute a bipolar transistor.

Abstract: In a semiconductor device having gold interconnections for connecting elements formed on a substrate with each other, the improvement is that the average dimension of gold grains constituting the gold interconnections is determined to be 0.17 through 0.25 times as large as width of the gold interconnections. In addition, the average dimension of the gold grains is determined so that the mean time to failure is not less than a predetermined period of time.

Abstract: A base region structure involved in a bipolar transistor, wherein the base region comprises a compound semiconductor epitaxial layer formed in a recessed portion provided by etching in an upper region of the semiconductor substrate and the recessed portion has a depth corresponding to a thickness of the compound semiconductor epitaxial layer so that the base region has a top surface positioned at the same level as a top surface of the semiconductor substrate.

Abstract: In a semiconductor device having gold interconnections for connecting elements formed on a substrate with each other, the improvement is that the average dimension of gold grains constituting the gold interconnections is determined to be 0.17 through 0.25 times as large as width of the gold interconnections.

Abstract: An ultraviolet radiation polymerizable unsaturated compound containing a polymerizable unsaturated group which is obtained by reacting a reaction product (I) prepared by the reaction between a higher fatty acid having 8 or more carbon atoms or an unsaturated monobasic acid, or a mixture of the two, and a polyisocyanate compound containing at least two isocyanate groups in the molecule, with a reaction product (II) prepared by the reaction between an unsaturated monobasic acid or a higher fatty acid having 8 or more carbon atoms, or a mixture of the two, and an epoxy compound containing at least two epoxy groups in the molecule.

Abstract: The invention provides a curable composition of polychloroprene, chlorinated polyethylene or polyepichlorohydrin containing at least one metal oxide having an oxidation state of 2 to 5 valences as a curing agent and at least one accelerator of the formulaA--(S).sub.n --A'wherein S is a sulfur atom, A and A' are polyhydroxy aryl groups having 6 to 18 ring carbon atoms and n is zero or an integer of 1 to 4. The accelerators enable a satisfactory rate and state of cure with the metal oxide.

Abstract: A polyolefin composition comprising polyolefin, a small amount of a ferrocene compound, and an 8-substituted quioline compound has excellent electrical breakdown strength, and therefore is suitable for electrical insulation.A polyolefin composition which is constructed by adding a small amount of a siloxane oligomer to the above polyolefin composition shows more improved electrical breakdown strength and also exhibits superior voltage endurance over a long period of immersion in water.