Nuclear Instruments and Methods in Physics Research B 240 (2005) 224–228 www.elsevier.com/locate/nimb
Iron distribution in the implanted silicon under the action of high-power pulsed ion and laser beams R. Bayazitov
a,*
, R. Batalov a, R. Nurutdinov a, V. Shustov a, P. Gaiduk b, I. De´zsi c, E. Ko´tai c
a
c
Kazan Physical-Technical Institute of RAS, Sibirsky Trakt 10/7, 420029 Kazan, Russia b Belarussian State University, F. Scarina Avenue 4, 220050, Minsk, Belarus KFKI Research Institute for Particle and Nuclear Physics, H-1525 Budapest 114, Hungary Available online 1 August 2005
Abstract The results of the investigation of the phase composition, microstructure and dopant depth distribution in silicon layers implanted with iron ions and annealed with pulsed ion and laser beams are given. X-ray diffraction data indicate the phase transition FeSi ! b-FeSi2 with increasing of the pulse energy density. After ion implantation and pulsed treatments, silicon layers have a cellular structure related with the low solubility of iron in silicon. Depending on the iron atomic concentration, either segregation of the dopant to the surface or diffusion into silicon takes place. This dependence is explained by rapid diffusion of iron in liquid silicon and increase of the dopant distribution coefficient when increasing dopant concentration. The results of the computer simulation agree well with experimental data on the iron depth distribution and give the segregation co-efficient close to 1 at the highest dopant concentration. 2005 Elsevier B.V. All rights reserved. PACS: 61.72.Tt; 61.80.x; 66.30.Jt; 73.61.Jc; 84.30.Ng Keywords: Silicon; Iron silicide; Ion implantation; Pulsed annealing; Diffusion; Segregation
1. Introduction Pulsed treatment of implanted semiconductors with laser, electron and ion beams is the efficient *
Corresponding author. Tel.: +7 8432 72 12 41; fax: +7 8432 72 50 75. E-mail address:
[email protected] (R. Bayazitov).
method to form highly doped layers and thin film compounds. Earlier was shown [1] that during pulsed ion beam treatment (PIBT) deeper diffusion than that at pulsed laser annealing (PLA) is observed resulting in the formation of deep highly doped layers. In the case of low-soluble impurities, such as iron in silicon (N 1016 cm3), in addition to diffusion, motion of the impurity to the surface
0168-583X/$ - see front matter 2005 Elsevier B.V. All rights reserved. doi:10.1016/j.nimb.2005.06.120
R. Bayazitov et al. / Nucl. Instr. and Meth. in Phys. Res. B 240 (2005) 224–228
(segregation) and synthesis of metal silicides takes place. Among different phases in the Fe–Si