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The Investigation of Intermediate Stage of Template Etching with Metal Droplets by Wetting Angle Analysis on (001) GaAs Surface

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ABSTRACT

In this work, we study metal droplets on a semiconductor surface that are the initial stage for both droplet epitaxy and local droplet etching. The distributions of droplet geometrical parameters such as height, radius and volume help to understand the droplet formation that strongly influences subsequent nanohole etching. To investigate the etching and intermixing processes, we offer a new method of wetting angle analysis. The aspect ratio that is defined as the ratio of the height to radius was used as an estimation of wetting angle which depends on the droplet material. The investigation of the wetting angle and the estimation of indium content revealed significant materials intermixing during the deposition time. AFM measurements reveal the presence of two droplet groups that is in agreement with nanohole investigations. To explain this observation, we consider arsenic evaporation and consequent change in the initial substrate. On the basis of our analysis, we suggest the model of droplet evolution and the formation of two droplet groups.

No MeSH data available.


The sketch of the evolution of metal droplet on the stable substrate (right) and in presence of a defect (left), resulting in rectangular and triangular profiles, respectively.
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Figure 4: The sketch of the evolution of metal droplet on the stable substrate (right) and in presence of a defect (left), resulting in rectangular and triangular profiles, respectively.

Mentions: We made the estimations for two simple models that are based on the nanohole investigation in the reference [15], where two groups of the nanoholes were observed that were called deep and flat due to the depth difference. Simplifying the nanohole geometry, we assume the etching profile to be rectangular or triangular (Figure 4). The first model might correspond to a low etching rate in the absence of any surface defect and consequently to a stable substrate providing uniform etching under the droplet. The second model describes the case of defect etching with a high rate, so the etching volume is limited by the crystal plates.


The Investigation of Intermediate Stage of Template Etching with Metal Droplets by Wetting Angle Analysis on (001) GaAs Surface
The sketch of the evolution of metal droplet on the stable substrate (right) and in presence of a defect (left), resulting in rectangular and triangular profiles, respectively.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211836&req=5

Figure 4: The sketch of the evolution of metal droplet on the stable substrate (right) and in presence of a defect (left), resulting in rectangular and triangular profiles, respectively.
Mentions: We made the estimations for two simple models that are based on the nanohole investigation in the reference [15], where two groups of the nanoholes were observed that were called deep and flat due to the depth difference. Simplifying the nanohole geometry, we assume the etching profile to be rectangular or triangular (Figure 4). The first model might correspond to a low etching rate in the absence of any surface defect and consequently to a stable substrate providing uniform etching under the droplet. The second model describes the case of defect etching with a high rate, so the etching volume is limited by the crystal plates.

View Article: PubMed Central - HTML - PubMed

ABSTRACT

In this work, we study metal droplets on a semiconductor surface that are the initial stage for both droplet epitaxy and local droplet etching. The distributions of droplet geometrical parameters such as height, radius and volume help to understand the droplet formation that strongly influences subsequent nanohole etching. To investigate the etching and intermixing processes, we offer a new method of wetting angle analysis. The aspect ratio that is defined as the ratio of the height to radius was used as an estimation of wetting angle which depends on the droplet material. The investigation of the wetting angle and the estimation of indium content revealed significant materials intermixing during the deposition time. AFM measurements reveal the presence of two droplet groups that is in agreement with nanohole investigations. To explain this observation, we consider arsenic evaporation and consequent change in the initial substrate. On the basis of our analysis, we suggest the model of droplet evolution and the formation of two droplet groups.

No MeSH data available.