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Dynamics of mass transport during nanohole drilling by local droplet etching.

Heyn C, Bartsch T, Sanguinetti S, Jesson D, Hansen W - Nanoscale Res Lett (2015)

Bottom Line: This paper studies the droplet material removal experimentally and discusses the results in terms of a simple model.Under consideration of these results, a simple kinetic scaling model of the etching process is proposed that quantitatively reproduces experimental data on the hole depth as a function of the process temperature and deposited amount of droplet material.Furthermore, the depth dependence of the hole side-facet angle is analyzed.

View Article: PubMed Central - PubMed

Affiliation: Institut für Angewandte Physik, Universität Hamburg, Jungiusstr. 11, Hamburg, 20355 Germany.

ABSTRACT
Local droplet etching (LDE) utilizes metal droplets during molecular beam epitaxy for the self-assembled drilling of nanoholes into III/V semiconductor surfaces. An essential process during LDE is the removal of the deposited droplet material from its initial position during post-growth annealing. This paper studies the droplet material removal experimentally and discusses the results in terms of a simple model. The first set of experiments demonstrates that the droplet material is removed by detachment of atoms and spreading over the substrate surface. Further experiments establish that droplet etching requires a small arsenic background pressure to inhibit re-attachment of the detached atoms. Surfaces processed under completely minimized As pressure show no hole formation but instead a conservation of the initial droplets. Under consideration of these results, a simple kinetic scaling model of the etching process is proposed that quantitatively reproduces experimental data on the hole depth as a function of the process temperature and deposited amount of droplet material. Furthermore, the depth dependence of the hole side-facet angle is analyzed.

No MeSH data available.


Related in: MedlinePlus

Measured and calculated hole side-facet angleα as function of the hole depth. Every data point represents the average over a sample with d varied by changing T and θ. In addition to calculations done using a model described in [47], results of a simple power-law fit are shown.
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Fig7: Measured and calculated hole side-facet angleα as function of the hole depth. Every data point represents the average over a sample with d varied by changing T and θ. In addition to calculations done using a model described in [47], results of a simple power-law fit are shown.

Mentions: For a complete characterization of the nanoholes, assuming as approximation an inverted cone-like shape (Figure 2d), in addition to the depth also, either the radius r=d/ tanα of the hole opening or the angle α between the hole side-facet and the flat surface is required. Figure 7 shows measured values of α for nanoholes where d was varied by the process parameters T and θ. Interestingly, the data indicate a systematic increase of θ with increasing d which is well reproduced by an empirical power law α≃8d0.4. Furthermore, Figure 7 demonstrates that an extension of the above model of the hole depth described in [47] also agrees well with the α vs. d data.Figure 7


Dynamics of mass transport during nanohole drilling by local droplet etching.

Heyn C, Bartsch T, Sanguinetti S, Jesson D, Hansen W - Nanoscale Res Lett (2015)

Measured and calculated hole side-facet angleα as function of the hole depth. Every data point represents the average over a sample with d varied by changing T and θ. In addition to calculations done using a model described in [47], results of a simple power-law fit are shown.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4385027&req=5

Fig7: Measured and calculated hole side-facet angleα as function of the hole depth. Every data point represents the average over a sample with d varied by changing T and θ. In addition to calculations done using a model described in [47], results of a simple power-law fit are shown.
Mentions: For a complete characterization of the nanoholes, assuming as approximation an inverted cone-like shape (Figure 2d), in addition to the depth also, either the radius r=d/ tanα of the hole opening or the angle α between the hole side-facet and the flat surface is required. Figure 7 shows measured values of α for nanoholes where d was varied by the process parameters T and θ. Interestingly, the data indicate a systematic increase of θ with increasing d which is well reproduced by an empirical power law α≃8d0.4. Furthermore, Figure 7 demonstrates that an extension of the above model of the hole depth described in [47] also agrees well with the α vs. d data.Figure 7

Bottom Line: This paper studies the droplet material removal experimentally and discusses the results in terms of a simple model.Under consideration of these results, a simple kinetic scaling model of the etching process is proposed that quantitatively reproduces experimental data on the hole depth as a function of the process temperature and deposited amount of droplet material.Furthermore, the depth dependence of the hole side-facet angle is analyzed.

View Article: PubMed Central - PubMed

Affiliation: Institut für Angewandte Physik, Universität Hamburg, Jungiusstr. 11, Hamburg, 20355 Germany.

ABSTRACT
Local droplet etching (LDE) utilizes metal droplets during molecular beam epitaxy for the self-assembled drilling of nanoholes into III/V semiconductor surfaces. An essential process during LDE is the removal of the deposited droplet material from its initial position during post-growth annealing. This paper studies the droplet material removal experimentally and discusses the results in terms of a simple model. The first set of experiments demonstrates that the droplet material is removed by detachment of atoms and spreading over the substrate surface. Further experiments establish that droplet etching requires a small arsenic background pressure to inhibit re-attachment of the detached atoms. Surfaces processed under completely minimized As pressure show no hole formation but instead a conservation of the initial droplets. Under consideration of these results, a simple kinetic scaling model of the etching process is proposed that quantitatively reproduces experimental data on the hole depth as a function of the process temperature and deposited amount of droplet material. Furthermore, the depth dependence of the hole side-facet angle is analyzed.

No MeSH data available.


Related in: MedlinePlus