A study of gettering efficiency and stability in Czochralski silicon

McHugo, Scott A.; Weber, E. R.; Mizuno, Masaya; Kirscht, F.G.

doi:10.1063/1.113447

Cited by 30 publications

(19 citation statements)

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“…The thermal stability of internally gettered iron has been studied by many authors, 23,29,30 and it is known that after a sufficiently long high temperature annealing iron will be completely dissolved. Zhang et al 30 studied the dissolution process in more detail using wafers with an oxide precipitate density of 5 ϫ 10 9 cm −3 , and the average radius was estimated to be 88 nm from decrease in the interstitial oxygen concentration.…”

Section: Dissolution Of Iron Precipitatesmentioning

confidence: 99%

“…E a is a fitting parameter which is related to surface energy and it also includes possible effects of strain [21][22][23] and the morphology 1 of oxide precipitates as well as the charge state 24 of iron. The practical numerical solution of the FPE, which is unconditionally stable and relatively larger time steps are allowed, is given in Ref.…”

Section: Model For Heterogeneous Precipitation Of Ironmentioning

confidence: 99%

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Experimental and theoretical study of heterogeneous iron precipitation in silicon

Haarahiltunen

Väinölä

Anttila

et al. 2007

Journal of Applied Physics

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Oxygen precipitation in nitrogen doped Czochralski silicon wafers. I. Formation mechanisms of near-surface and bulk defects J. Appl. Phys. 96, 3255 (2004) Heterogeneous iron precipitation in silicon was studied experimentally by measuring the gettering efficiency of oxide precipitate density of 1 ϫ 10 10 cm −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 ϫ 10 13 cm −3 drops to 3 ϫ 10 12 cm −3 , where as two lower initial iron concentrations of 5 ϫ 10 12 and 2 ϫ 10 13 cm −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.

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Section: Dissolution Of Iron Precipitatesmentioning

confidence: 99%

Section: Model For Heterogeneous Precipitation Of Ironmentioning

confidence: 99%

Experimental and theoretical study of heterogeneous iron precipitation in silicon

Haarahiltunen

Väinölä

Anttila

et al. 2007

Journal of Applied Physics

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“…All anneals were performed in a nitrogen atmosphere. The ramp step allows for oxygen precipitates to have a higher survival probability during the high temperature growth anneal and therefore provide a high concentration of internal gettering sites [14]. Laser Scattering Tomography (LST) measurements of defect densities revealed 10" defects/cm3 and 7x1 O7 defects/cm3 for samples with and without the IG formation anneals, respectively.…”

Section: Methodsmentioning

confidence: 99%

Copper in Silicon: Quantitative Analysis of Internal and Proximity Gettering

McHugo¹,

Heiser²,

Hieslmair³

et al. 1997

MSF

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The behavior of copper in the presence of a proximity gettering mechanism and a standard internal gettering mechanism in silicon was studied. He implantation-induced cavities in the near surface region were used as a proximity gettering mechanism and oxygen precipitates in the bulk of the material provided internal gettering sites. Moderate levels of copper contamination were introduced by ion implantation such that the copper was not supersaturated during the anneals, thus providing realistic copper contaminatiodgettering conditions. Copper concentrations at cavities and internal gettering sites were quantitatively measured after the annealings. In this manner, the gettering effectiveness of cavities was measured when in direct competition with internal gettering sites. The cavities were found to be the dominant gettering mechanism with only a small amount of copper gettered at the internal gettering sites. These results reveal the benefits of a segregation-type gettering mechanism for typical Contamination conditions.

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“…The growth temperature was 950 ' C for the samples which were contaminated with Cu and 980 C for those with Fe. The ramp treatment allows for the formation of a high concentration of internal gettering sites related to oxygen precipitation by slowly increasing the critical radius of the oxygen precipitate [16]. 1014 Cu atoms/cm2 were introduced =O.lpm deep on both the front and back sides by a 15OkeV implantation after He implantation but just prior to the gettering heat treatments.…”

Section: Methodsmentioning

confidence: 99%