Semiconductor device with a decoupling capacitor mounted thereon having a thermal expansion coefficient matched to the device

Claim 1

A semiconductor device, comprising: an insulating substrate having an exterior surface, a silicon semiconductor element having a coefficient of thermal expansion, a first exterior surface and a second exterior surface, the first exterior surface of the silicon semiconductor element being mounted on the exterior surface of the insulating substrate, and a decoupling capacitor joined to the second exterior surface of the silicon semiconductor element and electrically connected to the silicon semiconductor element, at least a portion of the semiconductor element being intermediate the exterior surface of the insulating substrate and the decoupling capacitor, wherein the decoupling capacitor is electrically connected to the silicon semiconductor element by soldering and has a first electrode film composed of at least one element selected from the group consisting of Al, Cr and Cu, a thin SiO 2 dielectric film and a second thin electrode film composed of at least one element selected from the group consisting of Al, Cr and Cu that are formed in this order on the surface of a substrate made of a material selected from the group consisting of silicon, Si 3 N 4 and SiC, having a coefficient of thermal expansion over a temperature range of from -65° to 150° C. which lies within ±0.8×10 -6 /°C. with respect to the coefficient of thermal expansion of the silicon semiconductor element.