Characterization of nonstoichiometric silicon nitride PECVD/ALD films for IR micro-detectors array

Selective absorption of nonstoichiometric silicon nitride (SixNy) thin films on silicon substrates was studied by infrared (IR) spectroscopy in the region of wavenumbers 500-7500 1/cm. For the transmission and reflection spectra of SixNy layers of various thicknesses the analysis of the absorption band of the Si-N stretching vibrations in the region 700-1100 1/cm with the peak at 820-900 1/cm was carried out. The absorption coefficient for IR radiation at wavenumber 850 1/cm was found to be about 1.02 1/um. The estimated absorption of IR radiation in SixNy layers with thicknesses in the range of 270-1300 nm was found of 45-64% depending on layer thickness.