DAMAGE RECOVERY IN ION-IMPLANTED TIO2 AT LOW-TEMPERATURES

Radiation damage was produced in [0 0 1] and [1 0 0] oriented TiO2 sin gle crystals by low dose (< 10(14)/cm(2)) high energy (260 keV) Hg-ion -implantation at 77 K and Xe-ion-implantation at 6 K. The Rutherford B ackscattering-Channeling (RBS-C) technique was used to measure the dam age peak areas of both sublattices as a function of time at 77 K and o f temperature in the region between 77 and 293 K. For moderate damage peak heights (less than 30% of the random level), annealing of about 8 0% of the defects occured within 3 recovery stages: (i) at 77 K (simil ar to 35%); (ii) at 160 K (similar to 25%); and (iii) at 280 K (20%). In stage (i) at 77 K, a time dependent recovery was observed. This has been attributed to a process that has an activation energy which incr eases with decreasing defect concentration. Stage (ii) is rather broad , indicating substages with different activation energies. Stage (iii) seems to occur in the Ti sublattice only, while the other stages reve al recovery in both sublattices. The Xe implants did not reveal pronou nced annealing between 6 and 62 K,The recovery stages at higher temper atures have been reproduced, indicating that intrinsic defect annealin g prevails. (C) 1998 Elsevier Science B.V. All rights reserved.