Silicon;
Dual low-energy ion implantation;
N implantation;
Pb implantation;
Electron beam annealing;
Pb diffusion;
Si nanowhisker formation;
SELF-ASSEMBLED SILICON;
NANOSTRUCTURES;
NANOCRYSTALS;
DIFFUSION;
SURFACE;
D O I:
10.1016/j.apsusc.2010.12.114
中图分类号:
O64 [物理化学(理论化学)、化学物理学];
学科分类号:
070304 ;
081704 ;
摘要:
(100) Si was dual ion-implanted with 24 key N and 7 key Pb to peak concentrations similar to 10 at.%. Implanted samples were then electron beam annealed (EBA) at a peak temperature T for 30 s with T ranging from 100 degrees C to 900 degrees C and for 15 s at 1000 degrees C. Pb profiles were measured using RBS and surfaces characterised by AFM. For T up to 500 degrees C there was no shift in the profile from the implanted depth similar to 10 nm. For higher values of T a striking feature was the large movement of the Pb profile away from the surface without a significant change in width or Pb content. The profile depths were: similar to 40 nm for 600 degrees C, similar to 68 nm for 700-900 degrees C and similar to 80 nm for 1000 degrees C. The response to EBA was found to be strongly dependent on both ion implantation order and Si starting structure. For (1 0 0)Si nanowhiskers formed on the treated surfaces for T=900 degrees C and 1000 degrees C. A model is developed based on the restructuring of the amorphous implanted layer under EBA. It is proposed that a compaction starting at the surface sweeps the Pb before it via a stress interaction as it advances into the Si. (c) 2011 Elsevier B.V. All rights reserved.