Dielectric loss of thin-film SiO$_{2}$ samples on Al in THz-IR range

The development of new dielectric materials for insulating layer of interconnects with low loss on high frequencies (low-$k$) is one of main directions of modern microelectronics. At present, various modifications of SiO$_2$-based dielectric structures standard for modern integrated circuits differ in composition and morphological characteristics are being studied. In this work, the dielectric loss of thin-film SiO$_2$ samples on Al substrate are studied by methods of terahertz (THz) and IR spectroscopy. It is found that the spectra of such structures are substantially different, including the resonant Berreman modes, as compared to the spectra of a bulk fused silica.