Interpolation of the spectral responsivity of silicon photodetectors in the near ultraviolet

We improve the methods used to interpolate the responsivity of unbiased sil icon photodetectors in the near-ultraviolet region. This improvement is ach ieved by the derivation of an interpolation function for the quantum yield of silicon and by consideration of this function in the interpolation of th e internal quantum efficiency of photodiodes. The calculated quantum-yield and spectral-responsivity values are compared with measurement results obta ined by the study of a silicon trap detector and with values reported by ot her research groups. The comparisons show agreement with a standard deviati on of 0.4% between our measured and modeled values for both the quantum yie ld and the spectral responsivity within the wavelength region from 260 to 4 00 nm. The proposed methods thus extend the predictability of the spectral responsivity of silicon photodetectors to the wavelength region from 260 to 950 nm. Furthermore, an explanation is proposed for the change in the spec tral responsivity of silicon photodiodes that is due to UV radiation. In ou r improved quantum efficiency model the spectral change can be accounted fo r completely by the adjustment of just one parameter, i.e., the collection efficiency near the SiO2/Si interface. (C) 2000 Optical Society of America OCIS codes: 120.5630, 040.6040, 040.7190, 230.5160.