| 摘要 |
PURPOSE:To plan for improving a sensitivity of capacity to voltage by a method wherein the same conductive type region having an inpurity concentration higher than an N type region is added to a P-N junction region and the P-N junction is brought close to the surface. CONSTITUTION:An N<+> region 6 formed by injecting ions is added to the variable capacity diode comprising an N type semiconductor substrate 1, N<1> layer 2, N-region 3, P<+>-region 4 and oxidized film 5. For his reason, the P-N junction JPN2 is located at a position near the surface as compared with that of the P-N junction JPN1 in case where the region 6 is not added. Furthermore, the impurity concentration sloping near the P-N junction JPN2 becomes radical depending on the region 6 formed by the ion injection of the impurity. Whereby an elongation of the depletion layer from the P-N junction JPN2 varies radically corresponding to the voltage variation. That is, the index of the capacity variation increases and the sensitivity of the capacity to the voltage is improved. |
