Gettering of iron by oxygen precipitates

Hieslmair, H.; Istratov, A. A.; McHugo, Scott A.; Flink, C.; Heiser, T.; Weber, E. R.

doi:10.1063/1.120592

Cited by 51 publications

(41 citation statements)

References 5 publications

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“…[6][7][8] Similarly, in multicrystalline silicon materials for solar cells, the overall impact of iron can be alleviated by driving iron precipitation at the crystallographic defects, [9][10][11][12] although the process is much less effective than the high temperature phosphorus diffusion gettering approach.…”

Section: Introductionmentioning

confidence: 99%

Gettering of interstitial iron in silicon by plasma-enhanced chemical vapour deposited silicon nitride films

Liu

Sun

Markevich

et al. 2016

Journal of Applied Physics

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It is known that the interstitial iron concentration in silicon is reduced after annealing silicon wafers coated with plasma-enhanced chemical vapour deposited (PECVD) silicon nitride films. The underlying mechanism for the significant iron reduction has remained unclear and is investigated in this work. Secondary ion mass spectrometry (SIMS) depth profiling of iron is performed on annealed iron-contaminated single-crystalline silicon wafers passivated with PECVD silicon nitride films. SIMS measurements reveal a high concentration of iron uniformly distributed in the annealed silicon nitride films. This accumulation of iron in the silicon nitride film matches the interstitial iron loss in the silicon bulk. This finding conclusively shows that the interstitial iron is gettered by the silicon nitride films during annealing over a wide temperature range from 250 °C to 900 °C, via a segregation gettering effect. Further experimental evidence is presented to support this finding. Deep-level transient spectroscopy analysis shows that no new electrically active defects are formed in the silicon bulk after annealing iron-containing silicon with silicon nitride films, confirming that the interstitial iron loss is not due to a change in the chemical structure of iron related defects in the silicon bulk. In addition, once the annealed silicon nitride films are removed, subsequent high temperature processes do not result in any reappearance of iron. Finally, the experimentally measured iron decay kinetics are shown to agree with a model of iron diffusion to the surface gettering sites, indicating a diffusion-limited iron gettering process for temperatures below 700 °C. The gettering process is found to become reaction-limited at higher temperatures.

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Section: Introductionmentioning

confidence: 99%

Gettering of interstitial iron in silicon by plasma-enhanced chemical vapour deposited silicon nitride films

Liu

Sun

Markevich

et al. 2016

Journal of Applied Physics

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“…1 Note that the dissolution time constant of 198 s at 800°C, albeit short, is much greater than a prediction based on the assumption that there is no dissolution barrier, i.e., that the redissolve process is only limited by iron diffusivity and solubility in silicon and the time constant ϭ1/(4nrD)ϭ2.53 s. It has been previously shown 12 that the effective iron density of the precipitate sites, obtained from iron precipitation kinetics using the same gettering temperatures and similar oxide precipitate density as in our experiments, is in a good agreement with the oxide precipitate density. Therefore, it is easy to show that if there were no dissolution barrier, the gettered iron would redissolve in less than 10 s at the annealing temperature of 800°C in CZ silicon with the density of the oxide precipitates as 5ϫ10 9 cm Ϫ3 , which corresponds to the interprecipitates distance 5.8 m.…”

Section: Thermal Stability Of Internal Gettering Of Iron In Silicon Amentioning

confidence: 85%

Thermal stability of internal gettering of iron in silicon and its impact on optimization of gettering

Zhang

Väinölä

Istratov

et al. 2003

Applied Physics Letters

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The redissolution behavior of gettered iron was studied in p-type Czochralski-grown silicon with a doping level of 2.5×1014 cm−3 and an oxide precipitate density of 5×109 cm−3. The concentrations of interstitial iron and iron–boron pairs were measured by deep level transient spectroscopy. It was found that the dependence of redissolved iron concentration on annealing time can be fitted by the function C(t)=C0[1−exp(−t/τdiss)], and the dissolution rate τdiss−1 has an Arrhenius-type temperature dependence of τdiss−1=4.01×104×exp[−(1.47±0.10) eV/kBT] s−1. Based on this empirical equation, we predict how stable the gettered iron is during different annealing sequences and discuss implications for optimization of internal gettering.

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“…The supersaturated oxygen atoms tend to aggregate thus forming oxide precipitates in Cz-Si during the device fabrication processes [1]. The oxide precipitates in the bulk of a Cz-Si wafer can act as the internal gettering (IG) sites for the detrimental metal contaminants [2][3][4]. However, the bulk oxide precipitate density could be reduced because the oxygen concentration in larger-diameter Cz-Si wafers and the thermal budgets of manufacturing integrated circuits are decreased to a certain extent.…”

Section: Introductionmentioning

confidence: 97%

Rapid thermal processing induced vacancy-oxygen complexes in Czochralski-grown Si1−xGex

Dong

Zhao

et al. 2015

J Mater Sci: Mater Electron

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Rapid thermal processing (RTP) induced vacancy-oxygen (VO m m C 2) complexes can act as the precursors for oxide precipitate nucleation thus enhancing oxygen precipitation (OP) in Czochralski silicon (Cz-Si). In our preceding work, we have reported that 10 20 cm -3 germanium (Ge)-doping in Cz-Si facilitates the formation of VO m complexes during the high temperature RTP. Then, how the even higher Ge-doping at 10 21 cm -3 in Cz-Si affects the formation of VO m complexes during the RTP is an interesting issue to be addressed. Actually, such high Ge-doping in Cz-Si forms Cz-Si 1-x Ge x alloys. In the present work, we have investigated the formation of VO m complexes in Cz-Si 1-x Ge x (x = 0.035-0.038) wafers subjected to the high temperature RTP. The Cz-Si 1-x Ge x wafers are found to exhibit much weaker OP than Cz-Si counterparts when subjected to the same two-step (nucleation-growth) anneal following the high temperature RTP, indicating that the formation of VO m complexes during the RTP is suppressed in Cz-Si

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Gettering of iron by oxygen precipitates

Cited by 51 publications

References 5 publications

Gettering of interstitial iron in silicon by plasma-enhanced chemical vapour deposited silicon nitride films

Gettering of interstitial iron in silicon by plasma-enhanced chemical vapour deposited silicon nitride films

Thermal stability of internal gettering of iron in silicon and its impact on optimization of gettering

Rapid thermal processing induced vacancy-oxygen complexes in Czochralski-grown Si1−xGex

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