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Atomic scale investigation of silicon nanowires and nanoclusters.

Roussel M, Chen W, Talbot E, Lardé R, Cadel E, Gourbilleau F, Grandidier B, Stiévenard D, Pareige P - Nanoscale Res Lett (2011)

Bottom Line: Intrinsic and p-type silicon nanowires (SiNWs) are elaborated by chemical vapor deposition method using gold as catalyst, silane as silicon precursor, and diborane as dopant reactant.The concentration and distribution of impurity (gold) and dopant (boron) in SiNW are investigated and discussed.Silicon nanoclusters are produced by thermal annealing of silicon-rich silicon oxide and silica multilayers.

View Article: PubMed Central - HTML - PubMed

Affiliation: Groupe de Physique des Matériaux, Université et INSA de Rouen, UMR CNRS 6634 - Av, de l'université, BP 12, 76801 Saint Etienne du Rouvray, France. manuel.roussel@etu.univ-rouen.fr.

ABSTRACT
In this study, we have performed nanoscale characterization of Si-clusters and Si-nanowires with a laser-assisted tomographic atom probe. Intrinsic and p-type silicon nanowires (SiNWs) are elaborated by chemical vapor deposition method using gold as catalyst, silane as silicon precursor, and diborane as dopant reactant. The concentration and distribution of impurity (gold) and dopant (boron) in SiNW are investigated and discussed. Silicon nanoclusters are produced by thermal annealing of silicon-rich silicon oxide and silica multilayers. In this process, atom probe tomography (APT) provides accurate information on the silicon nanoparticles and the chemistry of the nanolayers.

No MeSH data available.


Three-dimensional reconstruction of SRSO/SiO2 multilayer containing SiNCs. a. Distribution of silicon and b. oxygen atoms in the analyzed volume. Each dot corresponds to one atom. Silicon atoms belonging to SiNCs are artificially magnified for clarity. Arrows indicate the location of SRSO layers. c. Cross-sectional view of a SRSO layer.
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Figure 3: Three-dimensional reconstruction of SRSO/SiO2 multilayer containing SiNCs. a. Distribution of silicon and b. oxygen atoms in the analyzed volume. Each dot corresponds to one atom. Silicon atoms belonging to SiNCs are artificially magnified for clarity. Arrows indicate the location of SRSO layers. c. Cross-sectional view of a SRSO layer.

Mentions: Conventional analysis methods, such as PL measurements or HRTEM, are usually performed to characterize SiNCs. However, these techniques suffer from serious drawbacks, such as the complete detection of all the crystalline and amorphous clusters. The use of APT technique allows us to overcome most of these drawbacks and characterize all the SiNCs (amorphous or crystalline). The local composition measured by counting silicon and oxygen atoms for the SiO2 layers gives a composition of 34.3 ± 0.3 at.% of Si which is in close agreement with the theoretical composition (33.3 at.% of Si). SRSO layers contain 51.0 ± 0.3 at.% of Si which is the expected value following the elaboration process (50 at.% of Si). The ability of APT to measure local composition at the atomic scale allows studying the phase separation within these SRSO layers. Figure 3a, b represents the 3 D reconstruction image of the SRSO/SiO2 MLs. Each dot represents Si (red) and O (green). The Si atomic map (Figure 3a) evidences that precipitation occurs in the SRSO where two phases can be distinguished: Si-clusters and SiO2-matrix. The local composition measurements allow us to detect SiNCs, and a cluster identification algorithm is used for highlighting all the atoms which are surrounded by at least 75 at.% of Si. Thus, all the clusters, crystalline or amorphous, are evidenced. In addition, the silicon concentration in the matrix is significantly higher than in pure silica with a value reaching 41.9 ± 0.3 at.%. Silicon excess is still present in the matrix evidencing an incomplete phase separation between Si and SiO2 after an annealing treatment at 900°C during 1 h. This result confirms the slow phase separation process at such temperature as previously reported in similar systems [23,24]. Finally, the SiNCs appear to be homogeneously distributed in the SRSO layers (Figure 3c).


Atomic scale investigation of silicon nanowires and nanoclusters.

Roussel M, Chen W, Talbot E, Lardé R, Cadel E, Gourbilleau F, Grandidier B, Stiévenard D, Pareige P - Nanoscale Res Lett (2011)

Three-dimensional reconstruction of SRSO/SiO2 multilayer containing SiNCs. a. Distribution of silicon and b. oxygen atoms in the analyzed volume. Each dot corresponds to one atom. Silicon atoms belonging to SiNCs are artificially magnified for clarity. Arrows indicate the location of SRSO layers. c. Cross-sectional view of a SRSO layer.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211335&req=5

Figure 3: Three-dimensional reconstruction of SRSO/SiO2 multilayer containing SiNCs. a. Distribution of silicon and b. oxygen atoms in the analyzed volume. Each dot corresponds to one atom. Silicon atoms belonging to SiNCs are artificially magnified for clarity. Arrows indicate the location of SRSO layers. c. Cross-sectional view of a SRSO layer.
Mentions: Conventional analysis methods, such as PL measurements or HRTEM, are usually performed to characterize SiNCs. However, these techniques suffer from serious drawbacks, such as the complete detection of all the crystalline and amorphous clusters. The use of APT technique allows us to overcome most of these drawbacks and characterize all the SiNCs (amorphous or crystalline). The local composition measured by counting silicon and oxygen atoms for the SiO2 layers gives a composition of 34.3 ± 0.3 at.% of Si which is in close agreement with the theoretical composition (33.3 at.% of Si). SRSO layers contain 51.0 ± 0.3 at.% of Si which is the expected value following the elaboration process (50 at.% of Si). The ability of APT to measure local composition at the atomic scale allows studying the phase separation within these SRSO layers. Figure 3a, b represents the 3 D reconstruction image of the SRSO/SiO2 MLs. Each dot represents Si (red) and O (green). The Si atomic map (Figure 3a) evidences that precipitation occurs in the SRSO where two phases can be distinguished: Si-clusters and SiO2-matrix. The local composition measurements allow us to detect SiNCs, and a cluster identification algorithm is used for highlighting all the atoms which are surrounded by at least 75 at.% of Si. Thus, all the clusters, crystalline or amorphous, are evidenced. In addition, the silicon concentration in the matrix is significantly higher than in pure silica with a value reaching 41.9 ± 0.3 at.%. Silicon excess is still present in the matrix evidencing an incomplete phase separation between Si and SiO2 after an annealing treatment at 900°C during 1 h. This result confirms the slow phase separation process at such temperature as previously reported in similar systems [23,24]. Finally, the SiNCs appear to be homogeneously distributed in the SRSO layers (Figure 3c).

Bottom Line: Intrinsic and p-type silicon nanowires (SiNWs) are elaborated by chemical vapor deposition method using gold as catalyst, silane as silicon precursor, and diborane as dopant reactant.The concentration and distribution of impurity (gold) and dopant (boron) in SiNW are investigated and discussed.Silicon nanoclusters are produced by thermal annealing of silicon-rich silicon oxide and silica multilayers.

View Article: PubMed Central - HTML - PubMed

Affiliation: Groupe de Physique des Matériaux, Université et INSA de Rouen, UMR CNRS 6634 - Av, de l'université, BP 12, 76801 Saint Etienne du Rouvray, France. manuel.roussel@etu.univ-rouen.fr.

ABSTRACT
In this study, we have performed nanoscale characterization of Si-clusters and Si-nanowires with a laser-assisted tomographic atom probe. Intrinsic and p-type silicon nanowires (SiNWs) are elaborated by chemical vapor deposition method using gold as catalyst, silane as silicon precursor, and diborane as dopant reactant. The concentration and distribution of impurity (gold) and dopant (boron) in SiNW are investigated and discussed. Silicon nanoclusters are produced by thermal annealing of silicon-rich silicon oxide and silica multilayers. In this process, atom probe tomography (APT) provides accurate information on the silicon nanoparticles and the chemistry of the nanolayers.

No MeSH data available.