Investigation of optical phenomena in multispectral matrix photodetector based on silicon

A study is presented in the field of development and creation of modernized multi-layer color separation multispectral systems with increased color resolution. The types of structures of the developed patterns of matrix photodetectors based on multilayer silicon with working layers for use in the blue, green, red and infrared spectral ranges are considered. A method for calculating silicon layers in the form of optical films with specified characteristics is proposed. The silicon layers act as both a sensing element and a specific wavelength filter to highlight the blue, green, red and infrared ranges of the spectrum. The reflection and transmission coefficients were calculated for the selected wavelengths at various angles of incidence on the sensor. The Brewster angle for these wavelengths is also calculated. The possible presence of a microlens sensor surface is taken into account. Calculations are presented for cells with four-layer and two-layer structures for various combinations of layers. The dependences of the reflection and transmission coefficients for two-layer and four-layer structures of semiconductor sensors for p- and s-polarization, also for unpolarized light, are obtained. It is shown that the combination of layers in the red and infrared ranges of the spectra has the minimum reflection coefficient and the maximum transmission coefficient. The results obtained can be used in the development of multilayer multispectral systems with registration of infrared radiation. As a result, it is possible to use a pair of red and infrared spectra as the basis of a matrix photodetector pattern, and layers of blue and green spectra as auxiliary ones for building a full-color image.