Absorption Spectral Characteristics of Infrared Radiation in Silicon Dioxide Films for Thermal Radiation Detectors

Abstract

The absorption spectral characteristics of silicon dioxide films in the IR range (λ = 8–14 µm) were studied to determine the optimal absorber thickness in the matrix structure of Golay microcells in order to design highly sensitive IR detectors. It is shown that the absorbance spectrum of SiO₂ films deposited by electron-beam evaporation has a multipeak structure in the thickness range up to 2 µm and differs from the known absorption spectra of bulk silicon dioxide, which is apparently due to rearrangements in the film stoichiometry at the initial stages of film formation. Experiments have shown that the integrated absorption in deposited films in a given spectral range is close to a linear dependence on thickness and an order of magnitude smaller than the value obtained by calculation based on literature data for bulk SiO₂.