| 摘要 |
An image sensor is provided to prevent the entire area of a photodiode from being decreased while preventing electrons from being lost through the sidewall of a trench, by forming a P^+ epi layer in an isolated type within a trench so that the P^+ epi layer functions as an isolation layer and an N channel stop layer simultaneously and by forming a second P^- epi layer that surrounds the P^+ epi layer and has the same density as the first P^- epi layer so that a N^- diffusion layer for a photodiode is diffused to the second P^- epi layer. A first epi layer of a first conductivity type is formed on a substrate(110). A second epi layer of the first conductivity type is formed in a predetermined depth in the first epi layer. A third epi layer of the first conductivity type is formed in the first epi layer so as to surround the second epi layer, having a density lower than that of the second epi layer. A first diffusion layer for a photodiode is formed in the first and third epi layers to be aligned with one side of the second epi layer, having a second conductivity type. The third epi layer has the same doping density as the first epi layer.
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