| 摘要 |
PURPOSE:To obtain flat light output, in the Si light receiving device wherein an SiO2 is provided on an Si substrate, by selecting the film thickness so that the characteristic of the transmittance (a) of the incident light through said film can offset the spectral characteristic of Si in the specified wavelength region. CONSTITUTION:A P type base region 2 is diffused and formed in the surface layer part of the N type Si substrate 1. The entire surface including the region is coated by the SiO2 film 3. An opening is provided, and an Al base electrode 4 is attached in the region 2. Thus a photodiode is obtained. In this constitution, interference of the SiO2 film 3 is positively utilized, and the flat spectral characteristic is obtained in a broad wavelength region. That is, the film thickness d of the SiO2 film 3 is selected, so that d=0.5-0.55mum, and the incident wavelength (b) shown by the curve 3-2 makes downwardly convexed shape in the region of transmittance rate T(lambda)=600-900nm. Meanwhile, since the spectral characteristic of Si has upwardly convexed shape, they are offset each other out, and the spectral characteristic at lambda=650-850nm becomes flat. Therefore a filter is not required. |
