Press-contact flat type semiconductor device

Abstract

A press-contact flat type semiconductor device is disclosed which, without alloy-bonding a silicon pellet to a molybdenum or tungsten disc, assures a uniform press contact because a warp on the silicon pellet is largely reduced in comparison with a conventional device. A silver sheet is omitted between an anode electrode post and the silicon pellet to absorb a warp on the pellet. It is only necessary to insert a molybdenum or tungsten disc there, instead, which is thinner than a counterpart of the conventional device. Between the cathode electrode of the silicon pellet and a cathode electrode post use is made of, in the place of a conventional molybdenum foil and silver cap, an annealed soft copper cap of better malleability and, in the place of conventional molybdenum disc, an inexpensive hard copper sheet of adequate thickness and rigidity, not annealed, which can assure uniform press contact with the cathode electrode surface which oppositely confronts a gate lead connection circuit of a cathode electrode post. Since the silicon pellet is not alloy-bonded to the molybdenum or tungsten disc, it is simple and easy to form a bevelled structure, and to perform a silicone insulating rubber coating operation, so as to obtain the anode-to-cathode withstand voltage of the silicon pellet. Thus an inexpensive press-contact flat type semiconductor device of a long life can be provided which ensures more uniform press contact than a conventional semiconductor device.