| 摘要 |
PURPOSE:To obtain a diode featuring a high quantum efficiency and low redoubled noise by composing the avalanche photo diode with two kinds of semiconductor crystal materials. CONSTITUTION:P<->-type Si layer 2 is epitaxial-grown on N<+>-type Si substrate 1 and then covered with insulator 5. And the mesa etching is given deeper than PN junction 10 caused by drilling the opening to form concavity 6. Then N<+>-type layer 7 is formed through diffusion on the mesa slope of concavity 6, and film 5 is renewed with the window drilled at the center part of layer 2 to form concavity 2a to layer 2 through etching. After this, P<->-type Ge layer 3 is epitaxial-grown on the entire surface while filling concavity 6 and 2a. Then the P-type impurity is diffused to the surface of layer 3 to form P<+>-type Ge layer 4, and the surface of layer 4 is covered with film 5. Film 5 at the areas excluding layer 4 is removed along with layer 3 and 4 produced on the film, and surface electrode 8 is attached to remaining layer 4 with back surface electrode 9 attached to the back of the substrate. |
