Impurity effects in silicon implanted with rare-earth ions

Formation of donor centers in Czochralski-grown silicon doped with Dy, Ho, Er, and Yb by means of ion implantation is studied. Three kinds of donors w ith ionization energies less than 0.2 eV make their appearance in implanted Cz-Si after annealing at T = 700 degrees C and 900 degrees C, Shallow dono r centers at approximate to E-C - 40 meV are attributed to oxygen-related d onors. Two kinds of deeper donors turned out to be associated with complex defects containing rare-earth ions. (C) 1999 Elsevier Science B.V. All righ ts reserved.