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Morphology Analysis of Si Island Arrays on Si(001).

González-González A, Alonso M, Navarro E, Sacedón JL, Ruiz A - Nanoscale Res Lett (2010)

Bottom Line: The procedure reveals some noticeable features of these Si island arrays, e.g. a clear anisotropy of the in-plane local slope distributions.Total island volume analysis also indicates mass transport from the substrate surface to the 3D islands, a process presumably related to the presence of trenches around some of the pyramids.Results are discussed within the framework of similar island arrays in homoepitaxial and heteroepitaxial semiconductor systems.

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Affiliation: Instituto de Ciencia de Materiales de Madrid (ICMM-CSIC), C/Sor Juana Inés de la Cruz 3, Cantoblanco, Madrid, 28049 Spain.

ABSTRACT
The formation of nanometer-scale islands is an important issue for bottom-up-based schemes in novel electronic, optoelectronic and magnetoelectronic devices technology. In this work, we present a detailed atomic force microscopy analysis of Si island arrays grown by molecular beam epitaxy. Recent reports have shown that self-assembled distributions of fourfold pyramid-like islands develop in 5-nm thick Si layers grown at substrate temperatures of 650 and 750°C on HF-prepared Si(001) substrates. Looking for wielding control and understanding the phenomena involved in this surface nanostructuring, we develop and apply a formalism that allows for processing large area AFM topographic images in a shot, obtaining surface orientation maps with specific information on facets population. The procedure reveals some noticeable features of these Si island arrays, e.g. a clear anisotropy of the in-plane local slope distributions. Total island volume analysis also indicates mass transport from the substrate surface to the 3D islands, a process presumably related to the presence of trenches around some of the pyramids. Results are discussed within the framework of similar island arrays in homoepitaxial and heteroepitaxial semiconductor systems.

No MeSH data available.


AFM topography images (5 × 5 μm2) of Si pyramid-like arrays obtained growing nominally 5-nm thick Si layers on Si(001) substrates at different growth temperatures: aTg = 650°C and bTg = 750°C. The insets correspond to the respective self-correlation functions taken in sample regions of 2 × 2 μm2, revealing the quite regular order of both arrays
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Figure 1: AFM topography images (5 × 5 μm2) of Si pyramid-like arrays obtained growing nominally 5-nm thick Si layers on Si(001) substrates at different growth temperatures: aTg = 650°C and bTg = 750°C. The insets correspond to the respective self-correlation functions taken in sample regions of 2 × 2 μm2, revealing the quite regular order of both arrays

Mentions: Figure 1 shows AFM images of the surface morphology of Si layers (t = 5 nm) grown at substrate temperatures of Tg = 650 (Fig. 1a) and Tg = 750°C (Fig. 1b). Let us briefly comment some of the similarities and differences between them. Both surfaces exhibit arrays of 3D islands, which are mostly regular fourfold pyramids with square or rectangular bases, their edges preferentially running along the close-packed Si <110> directions [5]. Occasionally, two or more of these pyramid-like islands have coalesced, mainly along the corners. Representative results of the self-correlation function analysis performed on several AFM images are displayed as insets in Fig. 1a and 1b, for the respective sample growth temperature (Tg = 650 and Tg = 750°C). They clearly show that both island arrays exhibit a remarkable degree of order [4], which can be interpreted as indicative of self-assembly or self-organizing processes. We should note, however, that this study was carried out on selected image portions, where we tried to minimize the presence of coalesced island ensembles, because of their disturbing effects.


Morphology Analysis of Si Island Arrays on Si(001).

González-González A, Alonso M, Navarro E, Sacedón JL, Ruiz A - Nanoscale Res Lett (2010)

AFM topography images (5 × 5 μm2) of Si pyramid-like arrays obtained growing nominally 5-nm thick Si layers on Si(001) substrates at different growth temperatures: aTg = 650°C and bTg = 750°C. The insets correspond to the respective self-correlation functions taken in sample regions of 2 × 2 μm2, revealing the quite regular order of both arrays
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC2991161&req=5

Figure 1: AFM topography images (5 × 5 μm2) of Si pyramid-like arrays obtained growing nominally 5-nm thick Si layers on Si(001) substrates at different growth temperatures: aTg = 650°C and bTg = 750°C. The insets correspond to the respective self-correlation functions taken in sample regions of 2 × 2 μm2, revealing the quite regular order of both arrays
Mentions: Figure 1 shows AFM images of the surface morphology of Si layers (t = 5 nm) grown at substrate temperatures of Tg = 650 (Fig. 1a) and Tg = 750°C (Fig. 1b). Let us briefly comment some of the similarities and differences between them. Both surfaces exhibit arrays of 3D islands, which are mostly regular fourfold pyramids with square or rectangular bases, their edges preferentially running along the close-packed Si <110> directions [5]. Occasionally, two or more of these pyramid-like islands have coalesced, mainly along the corners. Representative results of the self-correlation function analysis performed on several AFM images are displayed as insets in Fig. 1a and 1b, for the respective sample growth temperature (Tg = 650 and Tg = 750°C). They clearly show that both island arrays exhibit a remarkable degree of order [4], which can be interpreted as indicative of self-assembly or self-organizing processes. We should note, however, that this study was carried out on selected image portions, where we tried to minimize the presence of coalesced island ensembles, because of their disturbing effects.

Bottom Line: The procedure reveals some noticeable features of these Si island arrays, e.g. a clear anisotropy of the in-plane local slope distributions.Total island volume analysis also indicates mass transport from the substrate surface to the 3D islands, a process presumably related to the presence of trenches around some of the pyramids.Results are discussed within the framework of similar island arrays in homoepitaxial and heteroepitaxial semiconductor systems.

View Article: PubMed Central - HTML - PubMed

Affiliation: Instituto de Ciencia de Materiales de Madrid (ICMM-CSIC), C/Sor Juana Inés de la Cruz 3, Cantoblanco, Madrid, 28049 Spain.

ABSTRACT
The formation of nanometer-scale islands is an important issue for bottom-up-based schemes in novel electronic, optoelectronic and magnetoelectronic devices technology. In this work, we present a detailed atomic force microscopy analysis of Si island arrays grown by molecular beam epitaxy. Recent reports have shown that self-assembled distributions of fourfold pyramid-like islands develop in 5-nm thick Si layers grown at substrate temperatures of 650 and 750°C on HF-prepared Si(001) substrates. Looking for wielding control and understanding the phenomena involved in this surface nanostructuring, we develop and apply a formalism that allows for processing large area AFM topographic images in a shot, obtaining surface orientation maps with specific information on facets population. The procedure reveals some noticeable features of these Si island arrays, e.g. a clear anisotropy of the in-plane local slope distributions. Total island volume analysis also indicates mass transport from the substrate surface to the 3D islands, a process presumably related to the presence of trenches around some of the pyramids. Results are discussed within the framework of similar island arrays in homoepitaxial and heteroepitaxial semiconductor systems.

No MeSH data available.