| 摘要 |
PURPOSE:To obtain a high speed diode characterized by a soft recovery characteristic and small noises at the time of mounting, by specifying the thickness of an N layer, carrier life, the depth X of rectifying junction, and impurity concentration NSP in the surface of a P layer of a diode having a P-N-N<+> structure, respectively. CONSTITUTION:In a P-N-N<+> structure, the following specifications are provided: the thickness of an N layer is 19-25mum; the carrier life of the N layer is 20-40ns; the depth of a current junction is 2-6mum; and the impurity concentration of the surface of the P layer is 8X10<18>atoms/cc or less. For example, an N layer 2 is epitaxially grown on an N<+> silicon substrate 1. Then the entire body is oxidized, and an N<++> layer 3 is formed on the lower surface. Thereafter, a hole is selectively provided in an SiO2 film 5 on the upper surface by photolithography. A P layer 4 is formed by using boron as P type impurities. A heavy metal is doped in the layer 4 as a life time killer. Thereafter, a field plate electrode 6 is evaporated on the upper surface, and a contact electrode 7 is evaporated on the lower surface. Finally pelletization is performed.
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