| 摘要 |
PURPOSE:To improve sensitivity, and to lower noises extremely by forming multi-periodic structure, in which one of mixed crystals consisting of Si, Ge and Sn is shaped in a lattice constant larger than a III-V compound semiconductor substrate and the other in a lattice constant smaller than the substrate, onto the substrate. CONSTITUTION:A Be-doped p-GaAs buffer layer 2, a p-SiGeSn multi-periodic layer 3 as an optical absorption layer, a p-SiGe lattice mismatching relaxing layer 3', and a p-Si layer 4 for avalanche multiplication are laminated onto a Zn-doped p<+>-GaAs substrate 1 in succession through a molecular beam epitaxial method. That is, Ge0.85 Sn0.15 having a lattice constant larger than GaAs and Si0.85Sn0.15 having a lattice constant smaller than GaAs are laminated alternately at every fifty period at every thickness such as 100Angstrom in the layer 3, and the Si1-zGeZ layer 3' is grown so that a composition (z) is reduced with separation from the substrate, and changed into the Si layer 4. Mutually opposite electrodes 7, 8 apply reverse bias voltage between 7 and 8, and the layers 4, 3', 3 are depleted toward the substrate side from an n<+>-p junction on the boundary of the layers 5, 4. Beams are projected through an SiO2 layer 6. |
