| 摘要 |
PURPOSE:To reduce surface reflection of a light and to provide a light confinement effect to high efficiency by forming grooves having an SiO2 film on either of a photodetecting surface or a rear surface. CONSTITUTION:A groove 21 of a photodetecting surface side and a groove 22 of a rear surface side are formed by etching with fluorinated nitric acid having no azimuth orientation, and an SiO2 film 41 of a photodetecting surface and an SiO3 film 42 of a rear surface are formed. The thickness of the film 41 is formed to satisfy a condition to minimize a reflectivity on the photodetecting surface side, and to satisfy a condition of increasing a reflectivity in the thickness of the film 42 on the rear surface side. The groove and the SiO3 film are formed on at least one of the photodetecting and rear surfaces. Part of the reflected light in the bottom of the groove of the photodetecting surface is radiated to the side of the groove, partly incident, and partly reflected. Further, part of the light reflected at the side of the groove is incident on the bottom of the groove or opposed surface. Thus, the part of the light reflected in the bottom and the side of the groove is enhanced for opportunity of incident operation, and hence the reflectivity of the entirety is reduced. |
