Abstract: Provided is a small-sized inexpensive semiconductor module in which increase of ON resistance and increase of turn-off surge voltage at low temperature are suppressed. The semiconductor module includes: a semiconductor switching element; and a stress application portion provided on one or each of a first surface and a second surface on an opposite side to the first surface of the semiconductor switching element, having a linear expansion coefficient larger than that of a main material of the semiconductor switching element, and having a larger thickness than the semiconductor switching element. The stress application portion generates compressive or tensile stress in the semiconductor switching element through thermal shrinkage or expansion of the stress application portion due to change in temperature. A threshold voltage at which the semiconductor switching element is turned on, decreases in association with increase of a magnitude of the compressive or tensile stress in the semiconductor switching element.

Abstract: This power conversion device includes: a semiconductor power module including a module busbar; a capacitor module including a capacitor element, a capacitor case formed in a bottomed tubular shape and storing the capacitor element with sealing resin interposed therebetween and a capacitor busbar having one end electrically connected to the capacitor element and another end extending outward from the capacitor case and electrically connected to the module busbar; and a power conversion device case formed in bottomed tubular shape and storing the semiconductor power module and the capacitor module. An outer surface of a bottom wall of the capacitor case and an inner surface of a bottom wall of the power conversion device case are thermally connected to each other. The capacitor module has a heat dissipation member located toward an opening side of the capacitor case relative to the capacitor element and thermally connected to the sealing resin.