29 29Si hyperfine interaction of two paramagnetic centersin Neutron-Irradiated SiliconSi

摘要

An electron spin resonance study has been carried out of twoparamagnetic centers in silicon. The first, Si-B3, is a tetragonal center ofwhich the full angular dependence of known and newly resolved 29 29Sihyperfine structure is revealed. Spectra simulations show that the defect wavefunction has its strongest hf interaction with two equivalent Si sites in a firstshell, a next interaction with four equivalent Si sites in a second shell, and alast interaction with eight equivalent Si sites in a third shell. The data complywith former theoretical calculations on the tetra-interstitial (I4), hence it isidentified with B3. The second unknown trigonal center, labelled Si-B5,exhibits two hf doublets corresponding with four and six equivalent Si sites.The tetra-interstitial I3 is proposed as a provisional defect model.