Limits...
Influence of surface properties on the electrical conductivity of silicon nanomembranes.

Zhao X, Scott SA, Huang M, Peng W, Kiefer AM, Flack FS, Savage DE, Lagally MG - Nanoscale Res Lett (2011)

Bottom Line: Two surface modifications, vacuum hydrogenation (VH) and hydrofluoric acid (HF) cleaning, of silicon nanomembranes (SiNMs) that nominally have the same effect, the hydrogen termination of the surface, are compared.Re-oxidation rates after these treatments also differ.We pinpoint the likely cause of the differences.PACS: 73.63.-b, 62.23.Kn, 73.40.Ty.

View Article: PubMed Central - HTML - PubMed

Affiliation: University of Wisconsin-Madison, Madison WI 53706, USA. lagally@engr.wisc.edu.

ABSTRACT
Because of the large surface-to-volume ratio, the conductivity of semiconductor nanostructures is very sensitive to surface chemical and structural conditions. Two surface modifications, vacuum hydrogenation (VH) and hydrofluoric acid (HF) cleaning, of silicon nanomembranes (SiNMs) that nominally have the same effect, the hydrogen termination of the surface, are compared. The sheet resistance of the SiNMs, measured by the van der Pauw method, shows that HF etching produces at least an order of magnitude larger drop in sheet resistance than that caused by VH treatment, relative to the very high sheet resistance of samples terminated with native oxide. Re-oxidation rates after these treatments also differ. X-ray photoelectron spectroscopy measurements are consistent with the electrical-conductivity results. We pinpoint the likely cause of the differences.PACS: 73.63.-b, 62.23.Kn, 73.40.Ty.

No MeSH data available.


Related in: MedlinePlus

Sheet resistance of 28-nm-thick Si membranes as a function of time. After VH and HF treatments (linear scales). The inset shows the sheet resistance (log scale) for the first 16 h after treatment, showing the crossover point in sheet resistances.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC3211497&req=5

Figure 2: Sheet resistance of 28-nm-thick Si membranes as a function of time. After VH and HF treatments (linear scales). The inset shows the sheet resistance (log scale) for the first 16 h after treatment, showing the crossover point in sheet resistances.

Mentions: Figure 1 also shows the initial evolution of the sheet resistance with time in an ambient (dry air) environment for both surface treatments. Figure 2 extends this time to 6 days for the thinner membrane. The inset (similar to Figure 1, but over a longer time) shows that for approximately the first hour, the sheet resistance of samples treated by VH increases faster than that of samples treated with HF, although the data in this regime are likely to be less reliable than for longer times. The sheet resistance of the HF-treated samples then increases more rapidly, crossing the sheet resistance of the VH-treated samples at approximately 8 h of exposure, after which time, the HF-treated samples become more resistive than those with the VH termination.


Influence of surface properties on the electrical conductivity of silicon nanomembranes.

Zhao X, Scott SA, Huang M, Peng W, Kiefer AM, Flack FS, Savage DE, Lagally MG - Nanoscale Res Lett (2011)

Sheet resistance of 28-nm-thick Si membranes as a function of time. After VH and HF treatments (linear scales). The inset shows the sheet resistance (log scale) for the first 16 h after treatment, showing the crossover point in sheet resistances.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211497&req=5

Figure 2: Sheet resistance of 28-nm-thick Si membranes as a function of time. After VH and HF treatments (linear scales). The inset shows the sheet resistance (log scale) for the first 16 h after treatment, showing the crossover point in sheet resistances.
Mentions: Figure 1 also shows the initial evolution of the sheet resistance with time in an ambient (dry air) environment for both surface treatments. Figure 2 extends this time to 6 days for the thinner membrane. The inset (similar to Figure 1, but over a longer time) shows that for approximately the first hour, the sheet resistance of samples treated by VH increases faster than that of samples treated with HF, although the data in this regime are likely to be less reliable than for longer times. The sheet resistance of the HF-treated samples then increases more rapidly, crossing the sheet resistance of the VH-treated samples at approximately 8 h of exposure, after which time, the HF-treated samples become more resistive than those with the VH termination.

Bottom Line: Two surface modifications, vacuum hydrogenation (VH) and hydrofluoric acid (HF) cleaning, of silicon nanomembranes (SiNMs) that nominally have the same effect, the hydrogen termination of the surface, are compared.Re-oxidation rates after these treatments also differ.We pinpoint the likely cause of the differences.PACS: 73.63.-b, 62.23.Kn, 73.40.Ty.

View Article: PubMed Central - HTML - PubMed

Affiliation: University of Wisconsin-Madison, Madison WI 53706, USA. lagally@engr.wisc.edu.

ABSTRACT
Because of the large surface-to-volume ratio, the conductivity of semiconductor nanostructures is very sensitive to surface chemical and structural conditions. Two surface modifications, vacuum hydrogenation (VH) and hydrofluoric acid (HF) cleaning, of silicon nanomembranes (SiNMs) that nominally have the same effect, the hydrogen termination of the surface, are compared. The sheet resistance of the SiNMs, measured by the van der Pauw method, shows that HF etching produces at least an order of magnitude larger drop in sheet resistance than that caused by VH treatment, relative to the very high sheet resistance of samples terminated with native oxide. Re-oxidation rates after these treatments also differ. X-ray photoelectron spectroscopy measurements are consistent with the electrical-conductivity results. We pinpoint the likely cause of the differences.PACS: 73.63.-b, 62.23.Kn, 73.40.Ty.

No MeSH data available.


Related in: MedlinePlus