Ceramic packaged semiconductor device

Claim 1

A semiconductor device comprising: an insulating substrate comprising a SiC ceramic containing 0.05 to 5% by weight of at least one of Be and a compound of Be in terms of Be element on the basis of total ceramic and having a relative density of not lower than 90% to the theoretical density, a coefficient of thermal expansion approximating that of a semiconductor material and a thermal conductivity not smaller than 0.2 cal/sec.cm. °C. at room temperature. at least one semiconductor element disposed at a predetermined location on one surface of said insulating substrate; a cap member made of alumina ceramic bonded to a preselected portion on one surface of the insulating substrate by a solder glass layer, thereby forming a package hermetically enclosing the semiconductor element together with the insulating substrate; and a terminal means having one end that is electrically connected to the semiconductor element within the package and another end that is exposed at the outside of said package, said terminal means being bonded to said insulating substrate by a sealing glass layer.