Defects and structure of µc‐SiO x :H deposited by PECVD

Electronic transport and paramagnetic defects detected by Electron Spin Resonance (ESR) in both intrinsic and -type silicon oxide prepared by PECVD were investigated. The structure and alloy composition of the material were varied all the way from microcrystalline silicon (µc-Si:H) to amorphous silicon oxide (a-SiOX:H). The transition-phase-mixture material is called “microcrystalline silicon oxide” (µc-SiOX:H). In undoped samples we find a strong reduction of the dark conductivity from 10-3to 10-12 S/cm and an increase of the spin density from1017 to 3×1019 cm-3 as the crystallinity decreases from 80% to 0%. The variation of the dark conductivity in phosphorous doped samples was even higher from 101 to 10-12 S/cm. ESR spectra of intrinsic material consist of a single featureless line with g-values in the range of 2.0043…2.005 depending on the structure and alloying. The spectra of -type material exhibit a broader range of g-values of 1.998…2.0043 due to strong variations of the Fermi level over the entire crystallinity range. The results are discussed within the frame of current understanding of µc-SiOX:H as a phase mixture of µc-Si:H crystallites embedded in a-SiOX:H matrix (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)