| 摘要 |
PURPOSE:To realize reduction of multiplied noise and improvement of high frequency response by providing an avalanche multiplication layer, formed by semiconductor material in which carrier multiplication is carried out by the resonant ionization, between a window layer and a photo-absorption layer and forming the pn junction in the window layer with separation from the avalanche multiplicationl layer. CONSTITUTION:A semiconductor photosensor is formed by an n<+>type GaSb substrate 1, an n-type GaSb photo-absorption layer 2, an n-type Al0.065Ga0.935Sb multiplication layer 3, an n-type AlxGa1-xSb window layer 4, a p<+>type region 5, a p side electrode 11 and an n side electrode 12 formed on the window layer 4. Although field intensity distribution gradually becomes weak toward the photoabsorption layer from the pn junction interface, the yielding of avalanche multiplication layer is generated here with such low field intensity as leaving a large margin for the avalanche yielding value of window layer and a large ionization ratio can be obtained. Thereby, large multiplication rate and low noise can be realized and high frequency response can be improved owing to quick rising of avalanche yield.
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