The electron paramagnetic resonance spectrum of a proton-related thermal donor, the NL8 paramagnetic center, was detected at 110K after heat treatment of H-implanted Czochralski-type material at 773K. The effect of temperature upon reversible transformations of the anisotropic spectrum of NL8 into an isotropic singlet line was studied at temperatures ranging from 110 to 240K. Analysis of the singlet provided evidence that this signal originated from a proton-related shallow donor at g = 1.9987. Changes in the line-width were used to evaluate the parameters for thermally activated electron emission to the conduction band from the second donor state of the NL8 center. The results constituted direct proof of reversible transformation of the TD+ charged center into a shallow donor-type center.

Electron paramagnetic resonance evidence for the reversible transformation of thermal donors into shallow donor-type centers in hydrogen-implanted silicon B.Rakvin, B.Pivac, R.Tonini, F.Corni, G.Ottaviani: Applied Physics Letters, 1998, 73[22], 3250-2