Microscopic structure of defects in microcrystalline silicon

Electron spin resonance (ESR) on paramagnetic defects in hydrogenated microcrystalline silicon (mu c-Si:H) has been studied to investigate its microscopic structure. From the anisotropy of preferentially oriented sample along (110) we suggest that the fine structure and its angular dependence arise from the grain boundary having (111) axial symmetry with g-tensors of g(perpendicular to) similar to 2.0022 and g(perpendicular to) similar to 2.0078 such as the Pb center. A simulation study indicates the presence of isotropic components arising from grain boundary defects on randomly oriented crystallites and dangling bonds in the amorphous structure. Thermal desorption of hydrogen from mu c-Si:H was correlated with the isochronal annealing of the ESR spectra. (C) 2000 Elsevier Science B.V. All rights reserved.