Abstract: A semiconductor device includes a semiconductor substrate having electrodes brazed thereto. The electrode is made of a Cu-C composite material in which carbon fibers are embedded in copper matrix. The carbon fibers are so disposed as to be in a ring-like shape or a loop shape substantially in parallel with a surface of the semiconductor substrate onto which the electrode is brazed. The carbon fibers disposed in an outer peripheral portion have a higher longitudinal elastic modulus than that of the carbon fibers positioned at a central portion of the electrode. The electrode thus has a thermal expansion coefficient approximating to that of the semiconductor substrate. Content of copper can be increased at the central portion of the electrode for attaining a high thermal conductivity.

Abstract: A bundle of carbon fibers each coated with copper or copper alloy is uniformly wound around a core rod under tension, and subjected to a hot press treatment in a non-oxidizing atmosphere. The core rod is then cut off along the surface of a plate formed by the hot-press to form a supporting electrode plate for a semiconductor device. The electrode plate thus fabricated incorporates therein carbon fibers in a spiral and concentric circular array around the core rod.