The eect of TEM sample thickness on nucleation and growth and dissolution of {311} defects in Si+ implanted

The eect of sample thickness on the nucleation, growth and dissolution of {311} defects in non-amorphizing 100 keV, 21014 cmÿ2 Si+ implanted Si has been investigated by plan-view transmission electron microscopy (PTEM) and cross-section TEM (XTEM). The samples were annealed at 8008C for times between 5 and 30 min. Results from samples annealed prior to TEM sample preparation were compared with samples annealed after thinning for TEM. The observed region in the TEM in both cases was 4000 A ̊ thick. TEM showed both the {311} extended defects and sub-threshold dislocation loops formed upon annealing. The depth distribution of these defects is centered around the ion damage profile. Quantitative TEM was used to measure the trapped interstitial concentration. The total interstitial concentration trapped in {311} defects and loops after annealing at 8008C for 5 min was determined to be 011014211013 cmÿ2 for the thick samples and 00.9 1014211013 cmÿ2 for the thin samples. The rate constant for {311} dissolution was determined from quantitative TEM to be 420 s for both the thick and thin samples. The existence of the second surface in the thin samples may aect the nucleation process slightly, but the existence of the second surface 2000 A ̊ below the implant layer has no measurable eect on the coarsening and dissolution of {311} defects and the evolution of the sub-threshold loops. This implies that the surface must be less than 2000 A ̊ from the implant layer to aect the interstitial evolution. # 1998 Elsevie