By simulating the line-shapes, at 9.8, 14, 20 and 35GHz, of a commonly observed S = 1/2 electron paramagnetic resonance center in polycrystalline chemical vapor deposited material, it was deduced that the electron paramagnetic resonance signal resulted from a defect with 1 or more H atoms which were about 0.2nm away from the unpaired electronic spin. It was suggested that H entered a vacancy-like stretched bond at a grain boundary; thus allowing the C atoms to relax backwards, with one bonding to the H atom and the other with an unpaired electron in its dangling bond. These results were expected to shed light on the phenomenon of H activation at grain boundaries in Si.

X.Zhou, G.D.Watkins, K.M.M.Rutledge: Materials Science Forum, 1995, 196-201, 825-30