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Memory properties and charge effect study in Si nanocrystals by scanning capacitance microscopy and spectroscopy.

Lin Z, Bremond G, Bassani F - Nanoscale Res Lett (2011)

Bottom Line: Scanning capacitance microscopy and spectroscopy were used to study the memory properties and charge effect in the Si nanocrystal in ambient temperature.The DC spectra curve shift direction and distance was observed differently for quantitative measurements.Holes or electrons can be separately injected into these Si-ncs and the capacitance changes caused by these trapped charges can be easily detected by scanning capacitance microscopy/spectroscopy at the nanometer scale.

View Article: PubMed Central - HTML - PubMed

Affiliation: Institut des Nanotechnologies de Lyon, UMR 5270, Institut National des Sciences Appliquées de Lyon, Université de Lyon, Bât, Blaise Pascal, 20, avenue Albert Einstein - 69621 Villeurbanne Cedex, France. zhen.lin@insa-lyon.fr.

ABSTRACT
In this letter, isolated Si nanocrystal has been formed by dewetting process with a thin silicon dioxide layer on top. Scanning capacitance microscopy and spectroscopy were used to study the memory properties and charge effect in the Si nanocrystal in ambient temperature. The retention time of trapped charges injected by different direct current (DC) bias were evaluated and compared. By ramp process, strong hysteresis window was observed. The DC spectra curve shift direction and distance was observed differently for quantitative measurements. Holes or electrons can be separately injected into these Si-ncs and the capacitance changes caused by these trapped charges can be easily detected by scanning capacitance microscopy/spectroscopy at the nanometer scale. This study is very useful for nanocrystal charge trap memory application.

No MeSH data available.


Related in: MedlinePlus

SCM image (a) and signal (b) versus different DC bias.
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Figure 3: SCM image (a) and signal (b) versus different DC bias.

Mentions: In order to investigate the effects of DC bias and alternating current (AC) bias to the SCM signal, the slowscan was disabled and a typical line scan was performed. In Figure 3a, the VAC bias was fixed to 2,500 mV. The SCM image and signal variation with DC bias is shown in Figure 3a. Different DC bias during the scan can cause different SCM signal. The best signal/noise ratio and highest contrast occurred when -1 or 0.5 V was applied, which is the same as Ge nanocrystals. Too high DC bias amplitude, such as up to 2 V, will make the SCM signal disappeared. Figure 3b illustrates this variation in function to the DC bias. The higher the DC bias amplitude, the stronger SCM signal intensity was. However, the lower the contrast between the Si-ncs and dielectric layer was. Positive or negative modulation corresponds to different SCM phase. The best resolution and the best signal to noise ratio which correspond to the highest contrast between Si-ncs and dielectric layer in the image was obtained near -0.5 and 0.5 V with the scan rate of 0.5 Hz.


Memory properties and charge effect study in Si nanocrystals by scanning capacitance microscopy and spectroscopy.

Lin Z, Bremond G, Bassani F - Nanoscale Res Lett (2011)

SCM image (a) and signal (b) versus different DC bias.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211215&req=5

Figure 3: SCM image (a) and signal (b) versus different DC bias.
Mentions: In order to investigate the effects of DC bias and alternating current (AC) bias to the SCM signal, the slowscan was disabled and a typical line scan was performed. In Figure 3a, the VAC bias was fixed to 2,500 mV. The SCM image and signal variation with DC bias is shown in Figure 3a. Different DC bias during the scan can cause different SCM signal. The best signal/noise ratio and highest contrast occurred when -1 or 0.5 V was applied, which is the same as Ge nanocrystals. Too high DC bias amplitude, such as up to 2 V, will make the SCM signal disappeared. Figure 3b illustrates this variation in function to the DC bias. The higher the DC bias amplitude, the stronger SCM signal intensity was. However, the lower the contrast between the Si-ncs and dielectric layer was. Positive or negative modulation corresponds to different SCM phase. The best resolution and the best signal to noise ratio which correspond to the highest contrast between Si-ncs and dielectric layer in the image was obtained near -0.5 and 0.5 V with the scan rate of 0.5 Hz.

Bottom Line: Scanning capacitance microscopy and spectroscopy were used to study the memory properties and charge effect in the Si nanocrystal in ambient temperature.The DC spectra curve shift direction and distance was observed differently for quantitative measurements.Holes or electrons can be separately injected into these Si-ncs and the capacitance changes caused by these trapped charges can be easily detected by scanning capacitance microscopy/spectroscopy at the nanometer scale.

View Article: PubMed Central - HTML - PubMed

Affiliation: Institut des Nanotechnologies de Lyon, UMR 5270, Institut National des Sciences Appliquées de Lyon, Université de Lyon, Bât, Blaise Pascal, 20, avenue Albert Einstein - 69621 Villeurbanne Cedex, France. zhen.lin@insa-lyon.fr.

ABSTRACT
In this letter, isolated Si nanocrystal has been formed by dewetting process with a thin silicon dioxide layer on top. Scanning capacitance microscopy and spectroscopy were used to study the memory properties and charge effect in the Si nanocrystal in ambient temperature. The retention time of trapped charges injected by different direct current (DC) bias were evaluated and compared. By ramp process, strong hysteresis window was observed. The DC spectra curve shift direction and distance was observed differently for quantitative measurements. Holes or electrons can be separately injected into these Si-ncs and the capacitance changes caused by these trapped charges can be easily detected by scanning capacitance microscopy/spectroscopy at the nanometer scale. This study is very useful for nanocrystal charge trap memory application.

No MeSH data available.


Related in: MedlinePlus