Study of the recrystallization of Si after implantation using different temperature and energy sequences

Si implanted at 2000C is known not to form an amorphous layer and to anneal less well than Si implanted at room temperature. Reasons for this difference and the implications of gradual wafer heating during implantation were studied. Ge was implanted into Si at room temperature and 2000C with energies of 200 keV and 350 keV respectively. Implantations were performed both singly and in sequence. The implanted and annealed samples were studied using RBS and TEM techniques. It was found that a 2000C implantation followed by one at room temperature behaves much like a simple superposition of the two. The presence of the amorphous surface layer does not affect the annealing of the deeper hot-implanted damage. However, for implantations performed in the reverse order, the second implantation causes some beam induced annealing of the pre-existing damage, and the subsequent total residual damage after annealing resembles that of a sample singly implanted at 2000C. (author)