An in situ annealing study of lead implanted single crystal calcium titanate

In situ annealing studies have been carried out in ion-implanted single crystals of CaTiO3. These crystals were implanted along both the a and b axes of this orthorhombic perovskite structure (Pcmn). Through the use of a Panasonic video cassette recorder connected to a Gatan television system on a JEOL 200CX transmission electron microscope, the regrowth process was observed and the growth rate monitored. Samples were annealed in a Gatan single tilt hot stage at ≅ 4750C. The near-surface region of this material, approximately 190 nm, is turned amorphous by the implantation of 540 keV Pb ions at a fluence of 1x1015/cm2. Annealing at 4750C results in the epitaxial regrowth of the damaged region. The regrowth process begins at the original amorphous/crystalline interface and proceeds outward to the surface. This phenomenon has been studied for implantations along both the (010) and the (100) crystallographic directions. For constant accelerating voltage and fluence of the implanted lead ions, transmission electron microscopy (TEM) and Rutherford backscattering spectroscopy (RBS) [C.W. White et al., to be published in Proc. of Radiation Effects in Insulators, Lyon, France, 1987.] indicate that the regrowth rate is linear with time but strongly dependent on the oxygen partial pressure in the annealing atmosphere, and the implantation and subsequent regrowth direction. (orig.)