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Growth and characterization of gold catalyzed SiGe nanowires and alternative metal-catalyzed Si nanowires.

Potié A, Baron T, Dhalluin F, Rosaz G, Salem B, Latu-Romain L, Kogelschatz M, Gentile P, Oehler F, Montès L, Kreisel J, Roussel H - Nanoscale Res Lett (2011)

Bottom Line: Ge concentration (x) in Si1-xGex NW has been successfully varied by modifying the gas flow ratio: R = GeH4/(SiH4 + GeH4).Second, the results of Si NW growths by CVD using alternatives catalysts such as platinum-, palladium- and nickel-silicides are presented.This approach allows the measurement of as-grown single NW's Young modulus and spring constant, and alleviates uncertainties inherent in single point measurement.

View Article: PubMed Central - HTML - PubMed

Affiliation: LTM/CNRS-CEA-LETI, 17, rue des martyrs, 38054 Grenoble, France. alexis.potie@cea.fr.

ABSTRACT
The growth of semiconductor (SC) nanowires (NW) by CVD using Au-catalyzed VLS process has been widely studied over the past few years. Among others SC, it is possible to grow pure Si or SiGe NW thanks to these techniques. Nevertheless, Au could deteriorate the electric properties of SC and the use of other metal catalysts will be mandatory if NW are to be designed for innovating electronic. First, this article's focus will be on SiGe NW's growth using Au catalyst. The authors managed to grow SiGe NW between 350 and 400°C. Ge concentration (x) in Si1-xGex NW has been successfully varied by modifying the gas flow ratio: R = GeH4/(SiH4 + GeH4). Characterization (by Raman spectroscopy and XRD) revealed concentrations varying from 0.2 to 0.46 on NW grown at 375°C, with R varying from 0.05 to 0.15. Second, the results of Si NW growths by CVD using alternatives catalysts such as platinum-, palladium- and nickel-silicides are presented. This study, carried out on a LPCVD furnace, aimed at defining Si NW growth conditions when using such catalysts. Since the growth temperatures investigated are lower than the eutectic temperatures of these Si-metal alloys, VSS growth is expected and observed. Different temperatures and HCl flow rates have been tested with the aim of minimizing 2D growth which induces an important tapering of the NW. Finally, mechanical characterization of single NW has been carried out using an AFM method developed at the LTM. It consists in measuring the deflection of an AFM tip while performing approach-retract curves at various positions along the length of a cantilevered NW. This approach allows the measurement of as-grown single NW's Young modulus and spring constant, and alleviates uncertainties inherent in single point measurement.

No MeSH data available.


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TEM image of a silicon NW (T = 800°C, PSiH4 = 60 mTorr, PHCl = 60 mTorr, 30 min) with PtSi catalyst at the top. The image shows a clearly faceted catalyst, suggesting that it remains solid during growth.
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Figure 4: TEM image of a silicon NW (T = 800°C, PSiH4 = 60 mTorr, PHCl = 60 mTorr, 30 min) with PtSi catalyst at the top. The image shows a clearly faceted catalyst, suggesting that it remains solid during growth.

Mentions: Since the temperatures investigated are less than the PtSi/Si eutectic temperature (979°C), NW are expected to grow via the vapour-solid-solid (VSS) mechanism. During the VSS growth, the catalyst remains solid at the top of the NW and enhances the adsorption and decomposition of the precursor. Figure 4 shows a TEM image of the PtSi catalyst at the top of a Si NW, which supports the previous hypothesis. Indeed, the catalyst particle is clearly crystalline. Unlike Au, PtSi does not form a spherical cap on the top of the NW. It remains strongly faceted or flat suggesting that catalyst does not melt - otherwise, surface tension forces would favor a spherical profile.


Growth and characterization of gold catalyzed SiGe nanowires and alternative metal-catalyzed Si nanowires.

Potié A, Baron T, Dhalluin F, Rosaz G, Salem B, Latu-Romain L, Kogelschatz M, Gentile P, Oehler F, Montès L, Kreisel J, Roussel H - Nanoscale Res Lett (2011)

TEM image of a silicon NW (T = 800°C, PSiH4 = 60 mTorr, PHCl = 60 mTorr, 30 min) with PtSi catalyst at the top. The image shows a clearly faceted catalyst, suggesting that it remains solid during growth.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211240&req=5

Figure 4: TEM image of a silicon NW (T = 800°C, PSiH4 = 60 mTorr, PHCl = 60 mTorr, 30 min) with PtSi catalyst at the top. The image shows a clearly faceted catalyst, suggesting that it remains solid during growth.
Mentions: Since the temperatures investigated are less than the PtSi/Si eutectic temperature (979°C), NW are expected to grow via the vapour-solid-solid (VSS) mechanism. During the VSS growth, the catalyst remains solid at the top of the NW and enhances the adsorption and decomposition of the precursor. Figure 4 shows a TEM image of the PtSi catalyst at the top of a Si NW, which supports the previous hypothesis. Indeed, the catalyst particle is clearly crystalline. Unlike Au, PtSi does not form a spherical cap on the top of the NW. It remains strongly faceted or flat suggesting that catalyst does not melt - otherwise, surface tension forces would favor a spherical profile.

Bottom Line: Ge concentration (x) in Si1-xGex NW has been successfully varied by modifying the gas flow ratio: R = GeH4/(SiH4 + GeH4).Second, the results of Si NW growths by CVD using alternatives catalysts such as platinum-, palladium- and nickel-silicides are presented.This approach allows the measurement of as-grown single NW's Young modulus and spring constant, and alleviates uncertainties inherent in single point measurement.

View Article: PubMed Central - HTML - PubMed

Affiliation: LTM/CNRS-CEA-LETI, 17, rue des martyrs, 38054 Grenoble, France. alexis.potie@cea.fr.

ABSTRACT
The growth of semiconductor (SC) nanowires (NW) by CVD using Au-catalyzed VLS process has been widely studied over the past few years. Among others SC, it is possible to grow pure Si or SiGe NW thanks to these techniques. Nevertheless, Au could deteriorate the electric properties of SC and the use of other metal catalysts will be mandatory if NW are to be designed for innovating electronic. First, this article's focus will be on SiGe NW's growth using Au catalyst. The authors managed to grow SiGe NW between 350 and 400°C. Ge concentration (x) in Si1-xGex NW has been successfully varied by modifying the gas flow ratio: R = GeH4/(SiH4 + GeH4). Characterization (by Raman spectroscopy and XRD) revealed concentrations varying from 0.2 to 0.46 on NW grown at 375°C, with R varying from 0.05 to 0.15. Second, the results of Si NW growths by CVD using alternatives catalysts such as platinum-, palladium- and nickel-silicides are presented. This study, carried out on a LPCVD furnace, aimed at defining Si NW growth conditions when using such catalysts. Since the growth temperatures investigated are lower than the eutectic temperatures of these Si-metal alloys, VSS growth is expected and observed. Different temperatures and HCl flow rates have been tested with the aim of minimizing 2D growth which induces an important tapering of the NW. Finally, mechanical characterization of single NW has been carried out using an AFM method developed at the LTM. It consists in measuring the deflection of an AFM tip while performing approach-retract curves at various positions along the length of a cantilevered NW. This approach allows the measurement of as-grown single NW's Young modulus and spring constant, and alleviates uncertainties inherent in single point measurement.

No MeSH data available.


Related in: MedlinePlus