| 摘要 |
PROBLEM TO BE SOLVED: To improve a response speed of a loading type avalanche photodiode without reducing the input resistance and the light reception sensitivity and the like.SOLUTION: A light absorption layer 109 is formed on a p-type electric field control layer 108, and configured by a p-type compound semiconductor, such as a p-type InGaAs. At least a part in a layer thickness direction, of the light absorption layer 109 is configured to have such an impurity concentration that a charge neutral condition is kept at operation. The light absorption layer 109 has an impurity concentration that is lower as it is closer to the p-type electric field control layer 108. |
