| 摘要 |
PURPOSE:To make carrier life time of a diode longer by a method wherein in a planar composition a junction area is made as large as possible keeping the allowable junction capacity and a width of a depletion layer which extends to the horizontal direction as small as possible keeping the required reverse dielectric strength. CONSTITUTION:An N type high impurity density layers (N<++> type layer) 2 are formed by diffusing high density N type impurity from both sides of an N type Si wafer 1 which has high resistivity and operates as an intrinsic (i-type) semiconductor layer. Then the layer 2 of one side is removed and the i-layer 1 is polished to the specified thickness and an SiO2 film 7 is formed on the polished surface. An aperture 8 is drilled in the film 7 and P type impurity is introduced through this aperture 8 and a P type layer 3 is formed. The area of the layer 3 is made as large as possible keeping the junction capacity within an allowable range. Then a circular aperture 9 surrounding the layer 3 is made in the SiO2 film 7 and high density N type impurity is introduced through this aperture 9 and an N<++> layer 10 is formed. Moreover, an anode 11 is formed to the side of the layer 2 and a cathode 12 and a planar type diode chip 13 are formed to the side of the layer 3. |
