ANNEALING BEHAVIOR OF KR ATOMS IN KR-IMPLANTED ALUMINUM

The behaviour of Kr atoms implanted into aluminium at room temperature with a dose of 1 x 10(15) Kr/cm(2) has been investigated by a channel ling method for isochronal annealing up to 683 K. In the as-implanted state the Kr atoms are distributed over tetrahedral (T), octahedral (O ), substitutional (S) and random (R) sites. On annealing at 433 and 59 3 K, the T- and O-site occupancies disappear, respectively, and in bot h cases the fraction of the S-site occupancy decreases and that of the R-site occupancy increases. The T- and O-site occupancies have been i nterpreted to be a result of the formation of Kr-vacancy (V) complexes of KrV4 and KrV6, respectively, and the R-site occupancy to be Kr ato ms associated with cavities. Therefore, the annealing stages at 433 an d 593 K are explained in terms of the dissociation of KrV4 and KrV6, r espectively. On annealing at 683 K, solid krypton is formed.