Back end of the line dielectrics (BEOL) with low dielectric constants, so called low-k dielectrics, are needed for current and future integrated circuit technology nodes. However, an understanding of the defects which limit reliability and cause leakage currents for these films is not yet developed. We primarily utilize conventional electron paramagnetic resonance (EPR) and leakage current measurements to investigate amorphous hydrogenated carbon doped oxide (a-SiOC:H) dielectrics, the most important in current BEOL technology. The resonance measurements were complemented by transmission Fourier-transform infra-red spectroscopy, x-ray reflectivity, and Rutherford backscattering measurements. Various compositions of a-SiOC:H films were deposited on 300 mm diameter Si (100) wafers. They exhibit a wide range of dielectric constant, composition, and porosity. Variations in deposition method, process chemistry, and post deposition curing were also investigated. We observe a remarkable range of paramagnetic defect populations within the films. In a large subset of the films with similar defect structure, we observe a strong correlation between carbon dangling bond paramagnetic defect densities and leakage currents, especially at lower electric fields. This correspondence strongly suggests that, in this subset, defects observed by EPR are in a large part responsible for the leakage currents at low electric fields. In addition, the results suggest that the observed defects likely limit the dielectric reliability in problems such as time dependent dielectric breakdown and stress induced leakage current in many of these films. However, the EPR results are complex, and a simple universal correspondence between defect populations and leakage does not seem to be present.

The electronic properties of low-κ interlayer dielectric and etch stop layers are important issues in ultralarge scale integrated circuits development. Leakage currents are critical problems that are not well understood. A topic of current interest is ultraviolet curing of these films. We report on electron spin resonance and electrical measurements of low-κ films with and without ultraviolet exposure. This work provides fundamental understanding of the deep level defects likely involved in leakage currents.

Color center formation was studied in vacuum sintered Nd3xY3−3xAl5O12 transparent ceramics. The primary color centers were F- and F+-centers as evidenced by optical absorption in the 250–400 nm wavelength range and the presence of an electron spin resonance (ESR) line at g=1.9977. Annealing in air at 1600 °C for 10 h reduced the number of color centers to below the detection limit of ESR. Color center formation is controlled by oxidation and reduction of Fe2+/3+ impurities.