| 摘要 |
PURPOSE:To obtain a glass-sealed type device which withstands a pressure with less forward voltage drop by laminating silicon wafers through the intermediary of molybdenum particles, alloying the silicon with aluminum soldering material and cutting a block to a prearranged size. CONSTITUTION:After P<+> and N<+> diffusion on N type silicon substrate, the both main surfaces are subjected to aluminium evaporation. The polarity of wafers 52a, 52b is set in the same direction and they are laminated through the intermediary of molybdenum particles 51. Following this process, the silicon is alloyed with aluminium soldering materials 23a, 23b at approximately 700 deg.C. A block thus formed is clad with an iron sheet mask, sand-blasted, cut and then is made into block pellets 61. With the use of molybdenum particles, a heat stress caused by a differential in coefficient of thermal expansion between silicon and molybdenum is insignificant. Therefore, the wafer does not have cracks. In addition, P type inversion layer is generated around the molybdenum particles, causing P type inversion layer on the N<+> layer to be ununiform, so that a forward voltage drop is reduced. Finally a molybdenum electrode lead is fixed on the main surface of the pellet 61 with aluminium soldering materials 23a, 23b to be finished with glass sealing. |
