For the tetra-interstitial agglomerate (I4), four additional Si atoms were incorporated into an ordinary unit cell of Si lattice in such a manner that all atoms were 4-coordinated and angles between bonds were not disturbed significantly. Microstructure, electrical properties, and formation mechanism of I4 in Si were inferred from the investigation of associated electron spin resonance spectra in various samples under various experimental conditions. It was found that the B3 electron spin resonance spectrum was related to a positive charge state of I4 and the NL51 spectrum was related to the excitonic state of the neutral defect. In Si samples pre-doped with H, formation of tetra-interstitial agglomerates after electron-irradiation and annealing was associated with various reactions of H with intrinsic defects.

Properties and Formation Mechanism of Tetra-Interstitial Agglomerates in Hydrogen-Doped Silicon. T.Mchedlidze, M.Suesawa: Physical Review B, 2004, 70[20], 205203 (9pp)