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Properties of silicon dioxide layers with embedded metal nanocrystals produced by oxidation of Si:Me mixture.

Novikau A, Gaiduk P, Maksimova K, Zenkevich A - Nanoscale Res Lett (2011)

Bottom Line: A two-dimensional layers of metal (Me) nanocrystals embedded in SiO2 were produced by pulsed laser deposition of uniformly mixed Si:Me film followed by its furnace oxidation and rapid thermal annealing.It is found that Me segregation induced by Si:Me mixture oxidation results in the formation of a high density of Me and silicide nanocrystals in thin film SiO2 matrix.Strong evidence of oxidation temperature as well as impurity type effect on the charge storage in crystalline Me-nanodot layer is demonstrated by the hysteresis behavior of the high-frequency C-V curves.

View Article: PubMed Central - HTML - PubMed

Affiliation: Belarusian State University, 4 prosp, Nezavisimosti, 220030, Minsk, Belarus. andrei.novikau.by@gmail.com.

ABSTRACT
A two-dimensional layers of metal (Me) nanocrystals embedded in SiO2 were produced by pulsed laser deposition of uniformly mixed Si:Me film followed by its furnace oxidation and rapid thermal annealing. The kinetics of the film oxidation and the structural properties of the prepared samples were investigated by Rutherford backscattering spectrometry, and transmission electron microscopy, respectively. The electrical properties of the selected SiO2:Me nanocomposite films were evaluated by measuring C-V and I-V characteristics on a metal-oxide-semiconductor stack. It is found that Me segregation induced by Si:Me mixture oxidation results in the formation of a high density of Me and silicide nanocrystals in thin film SiO2 matrix. Strong evidence of oxidation temperature as well as impurity type effect on the charge storage in crystalline Me-nanodot layer is demonstrated by the hysteresis behavior of the high-frequency C-V curves.

No MeSH data available.


The proposed procedure of the MOS stack formation including SiO2 layers with the embedded metal NCs.
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Figure 1: The proposed procedure of the MOS stack formation including SiO2 layers with the embedded metal NCs.

Mentions: N-type Si(001) wafers were used as substrates. The uniform SiO2 layer 6 nm in thickness (tunnel oxide) was first grown in a dry oxygen ambiance. An amorphous Si:Me (Me = Au, Pt) layer 20 nm in thickness was then deposited by PLD at room temperature. The computerized ultra-high vacuum (base pressure P = 10-6 Pa) home-made PLD setup employing YAG:Nd laser (λ = 1,064 μm) and operating in the Q-switched regime (τ = 15 ns) at the variable output energies E = 50-200 mJ and the repetition rates ν = 5-50 Hz was employed to ablate from the elemental Si and Me (Me = Au, Pt) targets. The pre-calculated composition of the Si:Me mixture necessary to form the desired nanocomposite structure was provided by choosing the exact ratio of Si vs. Me deposition pulses in a deposition cycle during the Si:Me layer growth. The sandwiched Si:Me/SiO2/Si samples were further thermally oxidized in dry oxygen ambient. To exclude the coalescence of the segregating metal NCs, the thermal budget should be minimized. Therefore, to determine the minimal temperatures to oxidize Si:Me mixtures at our conditions, the preliminary experiments were performed. It is worth noting that the presence of a noble metal in Si:Me mixture is found to significantly reduce the oxidation temperatures as compared to pure Si. Thus, the chosen oxidation conditions were T = 640-725°C for 60-540 min. Finally, the thermally oxidized structures were subjected to rapid thermal annealing in dry nitrogen ambient at T = 900°C for 30 s. The sequential processing steps are shown in Figure 1. A reference SiO2/Si sample with no metal NCs was prepared for comparison.


Properties of silicon dioxide layers with embedded metal nanocrystals produced by oxidation of Si:Me mixture.

Novikau A, Gaiduk P, Maksimova K, Zenkevich A - Nanoscale Res Lett (2011)

The proposed procedure of the MOS stack formation including SiO2 layers with the embedded metal NCs.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211198&req=5

Figure 1: The proposed procedure of the MOS stack formation including SiO2 layers with the embedded metal NCs.
Mentions: N-type Si(001) wafers were used as substrates. The uniform SiO2 layer 6 nm in thickness (tunnel oxide) was first grown in a dry oxygen ambiance. An amorphous Si:Me (Me = Au, Pt) layer 20 nm in thickness was then deposited by PLD at room temperature. The computerized ultra-high vacuum (base pressure P = 10-6 Pa) home-made PLD setup employing YAG:Nd laser (λ = 1,064 μm) and operating in the Q-switched regime (τ = 15 ns) at the variable output energies E = 50-200 mJ and the repetition rates ν = 5-50 Hz was employed to ablate from the elemental Si and Me (Me = Au, Pt) targets. The pre-calculated composition of the Si:Me mixture necessary to form the desired nanocomposite structure was provided by choosing the exact ratio of Si vs. Me deposition pulses in a deposition cycle during the Si:Me layer growth. The sandwiched Si:Me/SiO2/Si samples were further thermally oxidized in dry oxygen ambient. To exclude the coalescence of the segregating metal NCs, the thermal budget should be minimized. Therefore, to determine the minimal temperatures to oxidize Si:Me mixtures at our conditions, the preliminary experiments were performed. It is worth noting that the presence of a noble metal in Si:Me mixture is found to significantly reduce the oxidation temperatures as compared to pure Si. Thus, the chosen oxidation conditions were T = 640-725°C for 60-540 min. Finally, the thermally oxidized structures were subjected to rapid thermal annealing in dry nitrogen ambient at T = 900°C for 30 s. The sequential processing steps are shown in Figure 1. A reference SiO2/Si sample with no metal NCs was prepared for comparison.

Bottom Line: A two-dimensional layers of metal (Me) nanocrystals embedded in SiO2 were produced by pulsed laser deposition of uniformly mixed Si:Me film followed by its furnace oxidation and rapid thermal annealing.It is found that Me segregation induced by Si:Me mixture oxidation results in the formation of a high density of Me and silicide nanocrystals in thin film SiO2 matrix.Strong evidence of oxidation temperature as well as impurity type effect on the charge storage in crystalline Me-nanodot layer is demonstrated by the hysteresis behavior of the high-frequency C-V curves.

View Article: PubMed Central - HTML - PubMed

Affiliation: Belarusian State University, 4 prosp, Nezavisimosti, 220030, Minsk, Belarus. andrei.novikau.by@gmail.com.

ABSTRACT
A two-dimensional layers of metal (Me) nanocrystals embedded in SiO2 were produced by pulsed laser deposition of uniformly mixed Si:Me film followed by its furnace oxidation and rapid thermal annealing. The kinetics of the film oxidation and the structural properties of the prepared samples were investigated by Rutherford backscattering spectrometry, and transmission electron microscopy, respectively. The electrical properties of the selected SiO2:Me nanocomposite films were evaluated by measuring C-V and I-V characteristics on a metal-oxide-semiconductor stack. It is found that Me segregation induced by Si:Me mixture oxidation results in the formation of a high density of Me and silicide nanocrystals in thin film SiO2 matrix. Strong evidence of oxidation temperature as well as impurity type effect on the charge storage in crystalline Me-nanodot layer is demonstrated by the hysteresis behavior of the high-frequency C-V curves.

No MeSH data available.