Experimental and theoretical study of heterogeneous iron precipitation in silicon

Loading...
Thumbnail Image

Access rights

Copyright 2007 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. http://scitation.aip.org/content/aip/journal/jap
Final published version

URL

Journal Title

Journal ISSN

Volume Title

School of Electrical Engineering | A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä

Date

Major/Subject

Mcode

Degree programme

Language

en

Pages

7

Series

Journal of Applied Physics, Volume 101, Issue 4

Abstract

Heterogeneous iron precipitation in silicon was studied experimentally by measuring the gettering efficiency of oxide precipitate density of 1×10exp10cm−3. The wafers were contaminated with varying iron concentrations, and the gettering efficiency was studied using isothermal annealing in the temperature range from 300 to 780°C. It was found that iron precipitation obeys the so called s-curve behavior: if iron precipitation occurs, nearly all iron is gettered. For example, after 30 min annealing at 700°C, the highest initial iron concentration of 8×10exp13cm−3 drops to 3×10exp12cm−3, where as two lower initial iron concentrations of 5×10exp12 and 2×10exp13cm−3 remain nearly constant. This means that the level of supersaturation plays a significant role in the final gettering efficiency, and a rather high level of supersaturation is required before iron precipitation occurs at all. In addition, a model is presented for the growth and dissolution of iron precipitates at oxygen-related defects in silicon during thermal processing. The heterogeneous nucleation of iron is taken into account by special growth and dissolution rates, which are inserted into the Fokker-Planck equation. Comparison of simulated results to experimental ones proves that this model can be used to estimate internal gettering efficiency of iron under a variety of processing conditions.

Description

Other note

Citation

Haarahiltunen, Antti & Väinölä, Hele & Anttila, O. & Yli-Koski, Marko. 2007. Experimental and theoretical study of heterogeneous iron precipitation in silicon. Journal of Applied Physics. Volume 101, Issue 4. 0021-8979 (printed). DOI: 10.1063/1.2472271