| 摘要 |
PROBLEM TO BE SOLVED: To provide an APD assuring excellent internal quantum efficiency, dark current characteristic, response rate, and noise characteristic. SOLUTION: An end face incident waveguide-type APD of the multilayer structure includes at least an impurity-doped light absorbing layer, a couple of optical guide layers having a refractive index lower than that of light absorbing layer and sandwiching the light absorbing layer, and an undoped multiplying layer having the refractive index lower than that of the optical guide layer. One optical guide layer among the couple of optical guide layers formed sandwiching the light absorbing layer includes doped impurity in the same conductivity type as the light absorbing layer, while the other optical guide layer is formed of undoped semiconductor layer. The multiplying layer is formed in the side of the undoped optical guide layer. The refractive index of the semiconductor layer except for the light absorbing layer among the semiconductor layer forming the multilayer structure is lower than that of the light absorbing layer. COPYRIGHT: (C)2008,JPO&INPIT
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