A hot implantation study on the evolution of defects in He ion implanted MgO(1 0 0)

Abstract

Ion implantation at elevated temperature, so-called hot implantation, was used to study nucleation and thermal stability of the defects. In this work, MgO(1 0 0) single crystal samples were implanted with 30 keV He ions at various implantation temperatures. The implantation doses ranged from 1014 to 1016 cm-2. The implantation introduced defects were subsequently studied by thermal helium desorption spectroscopy (THDS) and Doppler broadening positron beam analysis (PBA). The THDS study provides vital information on the kinetics of He release from the sample. PBA technique, being sensitive to the open volume defects, provides complementary information on cavity evolution. The THD study has shown that in most cases helium release is characterised by the activation energy of Q = 4.7 ± 0.5 eV with the maximum release temperature of Tmax = 1830 K. By applying first order desorption model the pre-exponent factor is estimated as ν = 4.3 × 1011 s-1. © 2002 Published by Elsevier Science B.V.