An infrared study of the production, diffusion and complexing of interstitial boron in electron-irradiated silicon

Compensated silicon containing boron and a group V donor has been irradiated with 2 MeV electrons at a temperature of 110 K. LVM lines at 730 and 757 cm - 1 have been attributed to interstitial 11 B and 10 B atoms respectively. These defects anneal with second-order kinetics in the range 200-250 K leading to a diffusion coefficient D=0.04 exp(-0.58 eV/kT) cm 2 s -1 . Centres involving two equivalent boron atoms are formed and give LVM lines at 903, 912, 928 cm -1 ( omega /sub ///) and 599, 613, (624) cm -1 ( omega perpendicular to ) corresponding to a defect with axial symmetry. This centre anneals at a slightly higher temperature of 250-300 K to give the previously reported Q centre which shows one LVM line per isotope. At higher temperature this defect anneals, with the formation of nearest-neighbour (B-donor) substitutional pairs. A comparison is made with published results for B i centres obtained by the EPR and DLTS techniques.