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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.


Related in: MedlinePlus

SEM images of PtSi-catalyzed Si NW grown at 800°C for 10 min with different HCl partial pressures: (a) no HCl, (b) PHCl = 40, (c) PHCl = 100, (d) PHCl = 160 mtorr. Mean aperture angles (A) have been measured at the tip of the NW for each sample: (a) A = 14.4°, (b) A = 6.6°, (c) A = 3.4°, and (d) A = 2.7°. The aperture angle decreases when PHCl increases, which implies that the tapering effect is considerably reduced using gaseous HCl.
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Figure 5: SEM images of PtSi-catalyzed Si NW grown at 800°C for 10 min with different HCl partial pressures: (a) no HCl, (b) PHCl = 40, (c) PHCl = 100, (d) PHCl = 160 mtorr. Mean aperture angles (A) have been measured at the tip of the NW for each sample: (a) A = 14.4°, (b) A = 6.6°, (c) A = 3.4°, and (d) A = 2.7°. The aperture angle decreases when PHCl increases, which implies that the tapering effect is considerably reduced using gaseous HCl.

Mentions: To improve the growth selectivity, HCl gas is introduced into the deposition chamber along with SiH4. Figure 5 shows four NW samples grown without HCl and with three different HCl partial pressures (PHCl = 40, 100, and 160 mTorr). The NW are more or less cone shaped, and the mean aperture angle (formed by the sidewalls of the NW) has been measured on each sample. The mean aperture angle decreases from 14.4° without HCl to 2.7° with PHCl = 160 mTorr. The aperture angle is a measurement of the tapering of the NW. One can see that the tapering effect is reduced when PHCl increases, which is most probably due to a Cl surface coverage that inhibits the Si deposition on the sidewalls [31].


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)

SEM images of PtSi-catalyzed Si NW grown at 800°C for 10 min with different HCl partial pressures: (a) no HCl, (b) PHCl = 40, (c) PHCl = 100, (d) PHCl = 160 mtorr. Mean aperture angles (A) have been measured at the tip of the NW for each sample: (a) A = 14.4°, (b) A = 6.6°, (c) A = 3.4°, and (d) A = 2.7°. The aperture angle decreases when PHCl increases, which implies that the tapering effect is considerably reduced using gaseous HCl.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 5: SEM images of PtSi-catalyzed Si NW grown at 800°C for 10 min with different HCl partial pressures: (a) no HCl, (b) PHCl = 40, (c) PHCl = 100, (d) PHCl = 160 mtorr. Mean aperture angles (A) have been measured at the tip of the NW for each sample: (a) A = 14.4°, (b) A = 6.6°, (c) A = 3.4°, and (d) A = 2.7°. The aperture angle decreases when PHCl increases, which implies that the tapering effect is considerably reduced using gaseous HCl.
Mentions: To improve the growth selectivity, HCl gas is introduced into the deposition chamber along with SiH4. Figure 5 shows four NW samples grown without HCl and with three different HCl partial pressures (PHCl = 40, 100, and 160 mTorr). The NW are more or less cone shaped, and the mean aperture angle (formed by the sidewalls of the NW) has been measured on each sample. The mean aperture angle decreases from 14.4° without HCl to 2.7° with PHCl = 160 mTorr. The aperture angle is a measurement of the tapering of the NW. One can see that the tapering effect is reduced when PHCl increases, which is most probably due to a Cl surface coverage that inhibits the Si deposition on the sidewalls [31].

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