Lattice location studies of rare earth impurities in 3C-, 4H- and 6H-SiC

The lattice location of rare earths Tm in 3C- and 4H-SiC and Yb in 6H-SiC were studied using the emission channeling technique. Radioactive rare earth ions were implanted at the on-line isotope separator ISOLDE at CERN with an energy of 60 keV and fluences of 2 x 10(13) ions/cm(2). in order to determine the lattice location of the implanted impurities, angular dependent electron yields around certain axes were recorded with conversion electrons arising in the decay Tm-167-Er-167 (t(1/2) = 9.28 d) and Yb-169-Tm-169 (t(1/2) = 30.0 d). The effect of annealing on the normalized electron yields was studied up to 873 K for the 3C- and 4H-SiC samples and up to 1073 K for the 6H-SiC sample. In all cases the implanted rare earths are located on near substitutional silicon sites. (C) 2003 Elsevier B.V. All rights reserved.