Optimized Parameters for Modeling Oxygen Nucleation in Silicon

We investigated thermal oxide layers of different thickness on (100) and (111) silicon substrates by STEM/EELS to determine the stoichiometry profiles and compared these with stoichiometry profiles of plate-like and octahedral oxide precipitates in silicon. It was found that the stoichiometry of SiO x (x = 2) cannot be reached if the oxide layer thickness is lower than 10 nm for thermal oxides grown at 900 • C. This is due to an interface layer of equal maximum slope of x for all oxide layers. The slope of x is the change in stoichiometry with position and was obtained from fitting by sigmoid functions. Similar results were found for the oxide precipitates in silicon. However, there are arguments which question the slope determined via the low loss EEL spectra and the maximum x value could be closer to 2 in reality. On a sample with an oxide layer of 13.9 nm thickness we compared stoichiometry profiles obtained from the plasmon region and the Si-K 2,3 and O-K ionization edges. The width of the interface measured on stoichiometry profiles decreases with increasing energy loss and is lowest for the O-K ionization edge with a width of 1. In a previous work, we found that both the interface between an oxide precipitate and the surrounding silicon matrix and the interface between a silicon substrate and a thermal oxide layer are of the same nature.1 In both cases, between SiO 2 existing in the center of the precipitate and in the oxide layer and Si of the matrix and the substrate a suboxide region of 2-3 nm was found. These results were obtained by electron energy loss spectrometry (EELS) carried out by scanning transmission electron microscopy (STEM). In the low loss region, it is possible to distinguish between Si, SiO, and SiO 2 which all exhibit different maxima of the plasmon loss energy. By deconvolution, the local composition of the phase can be determined with the help of reference spectra of the three components.The stoichiometry of the oxide precipitates (SiO x ) was debated for a long time and application of different methods on different samples containing oxygen precipitates resulted in different values for x ranging from 1 to 2. Recently, it was demonstrated by applying several direct and indirect methods that the oxide precipitates consist of SiO 2 .2 Inspired by the results in Ref. 1 and 2, a layer model was proposed explaining the different experimental values for x for oxide precipitates of different geometry.3 Especially, for plate-like precipitates with a small aspect ratio the lower x values could be explained assuming that they consist of SiO 2 surrounded by a 2 nm SiO shell. However, neither is it known until now if all oxide precipitates consist of SiO 2 in the center nor is it known how thick the suboxide region for oxide precipitates grown at different temperature and time is. It needs to be mentioned that the suboxide region is not a layer of SiO composition but a profile of x increasing from the silicon matrix to the SiO 2 core. The impression of a layer just stems from the analysis of ele...

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“…Ref. 16). Our results offer further possibilities to obtain experimental results which can be used to determine the interface energy.…”

Section: Resultsmentioning

confidence: 99%

Investigation of the Composition of the Si/SiO₂Interface in Oxide Precipitates and Oxide Layers on Silicon by STEM/EELS

Kissinger

Schubert

Kot

et al. 2017

ECS J. Solid State Sci. Technol.

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“…We wanted to use a second method to confirm the EELS results and have chosen ToF-SIMS. We recorded depth profiles of the following species: O -, 18 O -, 30 Si -, SiO -, SiO conditions in the measurement chamber. We assumed that the species Oand 18 Ostem from the residual air in the chamber and used all the other species to calculate the stoichiometry profiles.…”

Section: Resultsmentioning

confidence: 99%

Investigation of the Composition of the Si/SiO₂ Interface in Oxide Precipitates and Oxide Layers on Silicon by STEM/EELS

Kissinger¹,

Schubert²,

Kot³

et al. 2016

ECS Trans.

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We investigated thermal oxide layers of different thickness on (100) and (111) silicon substrates by STEM/EELS in order to determine the stoichiometry profiles and compared these with stoichiometry profiles of plate-like and octahedral oxide precipitates in silicon. The results of these investigations demonstrate that the stoichiometry of SiO2 (x=2) cannot be reached if the oxide layer thickness is lower than 10 nm for thermal oxides grown at 900 °C. The lower the thickness of the layer is the lower is the maximum x value. This is due to an interface layer of equal maximum slope for all oxide layers. The slope was obtained from fitting by sigmoid functions. Similar results were found for the oxide precipitates in silicon but the slope is somewhat lower.

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“…3 in a similar way as described in Ref. 4. Two cases were simulated, oxygen clustering without grown-in nuclei describing the pure nucleation during ramping and clustering with grown-in nuclei of different size.…”

mentioning

confidence: 99%

Verification of a Method to Detect Grown-in Oxide Precipitate Nuclei in Czochralski Silicon

Kissinger,

Sattler,

Dabrowski

et al. 2007

Meet. Abstr.

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Optimized Parameters for Modeling Oxygen Nucleation in Silicon

Cited by 3 publications

References 9 publications

Investigation of the Composition of the Si/SiO₂Interface in Oxide Precipitates and Oxide Layers on Silicon by STEM/EELS

Investigation of the Composition of the Si/SiO₂Interface in Oxide Precipitates and Oxide Layers on Silicon by STEM/EELS

Investigation of the Composition of the Si/SiO₂ Interface in Oxide Precipitates and Oxide Layers on Silicon by STEM/EELS

Verification of a Method to Detect Grown-in Oxide Precipitate Nuclei in Czochralski Silicon

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Optimized Parameters for Modeling Oxygen Nucleation in Silicon

Cited by 3 publications

References 9 publications

Investigation of the Composition of the Si/SiO2Interface in Oxide Precipitates and Oxide Layers on Silicon by STEM/EELS

Investigation of the Composition of the Si/SiO2Interface in Oxide Precipitates and Oxide Layers on Silicon by STEM/EELS

Investigation of the Composition of the Si/SiO2 Interface in Oxide Precipitates and Oxide Layers on Silicon by STEM/EELS

Verification of a Method to Detect Grown-in Oxide Precipitate Nuclei in Czochralski Silicon

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Investigation of the Composition of the Si/SiO₂Interface in Oxide Precipitates and Oxide Layers on Silicon by STEM/EELS

Investigation of the Composition of the Si/SiO₂Interface in Oxide Precipitates and Oxide Layers on Silicon by STEM/EELS

Investigation of the Composition of the Si/SiO₂ Interface in Oxide Precipitates and Oxide Layers on Silicon by STEM/EELS