| 摘要 |
PURPOSE:To reduce an irregularity in an electrical characteristic by a method wherein semiconductor porcelains on which a diffusion agent has been coated in advance uniformly and dried are housed regularly in recessed parts of a sheath so as to come into equal contact with one another and heat-treated so as to insulate a crystal grain boundary. CONSTITUTION:A diffusion agent paste of a prescribed amount is coated on semiconductor porcelains and dried; after that, the semiconductor porcelains 3 on which a diffusion agent has been coated are housed regularly in an alumina sheath 7 where many cylindrical recessed parts 1a have been made. The semiconductor porcelains 3 which have been filled into the sheath are heat-treated in the air at 1100 deg.C for 4 hours. By this heat treatment the diffusion agent is diffused to a crystal grain boundary of the semiconductor porcelains; this grain boundary is insulated. By this setup, it is possible to restrain the diffusion agent from being evaporated into the air, to reduce an irregularity in a residual amount of the diffusion agent after the heat treatment and to reduce an irregularity in an electrical characteristic. |
