Observation of dynamic annealing effects in oxide single crystals after high-dose18O+implantation at 500 °C

Abstract

Dynamic annealing effects and the behavior of oxygen trapping and migration in the perovskite oxide single crystals following high dose ${}^{18}{\mathrm{O}}^{+}$ implantation at 500 \ifmmode^\circ\else\textdegree\fi{}C and at room temperature have been studied. We report that the cascade collision induced by room-temperature irradiation with ${}^{18}\mathrm{O}$ ions (200 keV $5\ifmmode\times\else\texttimes\fi{}{10}^{16}/{\mathrm{cm}}^{2}$) into ${\mathrm{SrTiO}}_{3}$ single crystal induces an essentially amorphous $({\ensuremath{\chi}}_{\mathrm{min}}\ensuremath{\approx}96%)$ surface layer to a depth of 400 nm. However, irradiation at 500 \ifmmode^\circ\else\textdegree\fi{}C results in dynamic annealing effects since ion channeling shows ${\ensuremath{\chi}}_{\mathrm{min}}$ of 3% in the near surface region. ${}^{18}\mathrm{O}$ depth profiles measured by the ${}^{18}\mathrm{O}(p,\ensuremath{\alpha}{)}^{15}\mathrm{N}$ nuclear reaction show that high-temperature implantation results in a flat-topped ${}^{18}\mathrm{O}$ distribution with only 48% (compared with room-temperature implantation) of implanted ${}^{18}\mathrm{O}$ retained, and more importantly, channeled nuclear reaction analysis shows that at least 77% of the retained ${}^{18}\mathrm{O}$ occupies substitutional sites. Room-temperature implantation plus post-irradiation annealing at 500 \ifmmode^\circ\else\textdegree\fi{}C in flowing oxygen ambient resulted in much less recovery of irradiation damage (${\ensuremath{\chi}}_{\mathrm{min}}\ensuremath{\approx}33$ to 72%). Similar effects were observed in ${}^{18}\mathrm{O}$ implanted single crystal ${\mathrm{LaAlO}}_{3}.$