Defect formation inSi(111)7×7surfaces due to 200 eVAr+

Abstract

Surface x-ray diffraction measurements have been made to study defect formation at the atomic level in the near surface region of Si(111)7ϫ7 surface during low energy ͑200 eV͒ Ar ϩ ion bombardment. We have observed the two characteristics of the defects: missing atoms at different layers in the surface region as well as outward strain. We provide calculations that demonstrate how crystal truncation rod ͑CTR͒ measurements are sensitive to these modifications in the surface regions. We find that the measurement is sensitive to lattice strain and site occupancy of individual atomic layers near to the surface. We have thus determined occupancy profiles that represent the density of missing atoms with depth after irradiation. Both the strain and the atom deficit are found to increase with dose while the two distributions extend to about the same depth. These results are consistent with simulations of the ion-solid interaction mechanism using SRIM2000 with appropriate choice of surface and bulk displacement energies.

Structural Characterization of Ar+-Irradiated SrTiO3 Showing Room-Temperature Blue Luminescence

“…This hypothesis is reasonable for our system because defects caused by low energy Ar ion implantation in the surface region of the (111)Si also showed an exponential-type distribution. 10) We therefore introduce the following form for the distribution in the lattice parameter of the k-th tetragonal STO along ð00LÞ,…”