| 摘要 |
In a first diffusion region constituting a photodiode in each pixel, carriers generated in response to incoming light are accumulated. A second diffusion region is formed on the surface of the first diffusion region to cover an outer circumference part of the first diffusion region. In the outer circumference part of the first diffusion region, crystal defects are easily generated due to a process of forming an element isolating region and a process of forming a gate electrode, and dark current noise is easily generated. The second diffusion region functions as a protection layer for preventing the crystal defects from being generated in the manufacturing process. The second diffusion region is not formed on a center portion on the surface of the first diffusion region where the crystal defects are not easily generated. Since the thickness of a depletion layer in the first diffusion region whereupon the second diffusion region is not formed can be increased, light detection sensitivity can be improved. As a result, detection sensitivity of the photodiode can be improved without increasing dark current noise.
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