| 摘要 |
PURPOSE:To prevent the increase of dark current by a method wherein a Ge wafer is applied impurity diffusion or heat treatment by utilizing a mask material resembling Ge in the coefficient of thermal expansion. CONSTITUTION:The mask of a material (Si3N4 or Al2O3) whose coefficient of thermal expansion resembles to that of Ge is applied on the Ge wafer 1 to be formed an opening, after being applied thermal diffusion of Sb to form a guard ring region 3 coated again by Si3N4 or Al2O3 to be formed an opening, and heat-diffused with As to form a light receiving part 4 and then, the Ge surface is removed by an etching liquid. Subsequently, SiO2, Al2O3 film 5, 6 (the film 5 is made an antihalation film) are mounted to form an Al electrode 7 thereon. Thereby, since a strain of the Ge by the increase of a heat cycle does not appear, the dark current is prevented from increasing. |
