ELECTRON-PARAMAGNETIC-RESONANCE IDENTIFICATION OF HYDROGEN-PASSIVATED SULFUR CENTERS IN SILICON

Two centers are detected in hydrogenated sulfur-doped silicon by means of electron paramagnetic resonance. Both defects, labeled for further reference Si-NL54 and Si-NL55, are very similar and have trigonal symmetry; to better resolve the spectra, the field-scanned electron nuclear double resonance (ENDOR) technique has been used. The ratio of the intensities of both spectra remained the same after various quenching procedures, suggesting their formation to be (almost) of the same relative probability. Isotopically enriched sulfur was used and disclosed the involvement of one sulfur atom in each center. In ENDOR hyperfine interactions with hydrogen, one atom per center, have been observed. Extra evidence of the involvement of hydrogen in these defects was found by doping with deuterium. Based on the experimental evidence the defects are identified as two forms of a (substitutional) sulfur double donor in the neutral charge state, passivated with a single hydrogen atom, i.e., (S-H)0 pairs. Such an identification is supported by infrared absorption measurements. © 1995 The American Physical Society.