Polar optical phonons in superlattices Si/SiO$_2$

A study was carried out of the dielectric properties of planar Si/SiO$_2$ heterostructures, which play an important role in modern electronics. Using the model of dielectric continuum, the spectra of polar phonons in Si/SiO$_2$ binary superlattices have been studied. Quartz and cristobalite lattices are considered as a structural model of the oxide layer. The dependences of polar optical phonons frequencies and the high-frequency dielectric constant tensor elements on the ratio of layer thicknesses were obtained. The results obtained open up the possibility of using spectroscopic data to characterize the structure of superlattices.