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arXiv · 1611.06836

Nano patterns self-aligned to Ga dimer rows on GaAs surfaces

Martin Engler·Tomáš Škereň·Stefan Facsko
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Abstract

Ion beam irradiation of semiconductors is a method to produce regular periodic nanoscale patterns self-organized on wafer scale. At low temperatures, the surface of semiconductors is typically amorphized by the ion beam. Above a material dependent dynamic recrystallization temperature however, the surface remains crystalline and ion beam irradiation produces regular arrays of faceted ripples on III-V semiconductors. This provides a powerful single-step technique for the production of nanostructures on a large area. On $(001)$ surfaces these ripples are parallel to the $[1\bar{1}0]$ direction without any external anisotropy. The origin of this self-alignment was not fully understood until now. A simple experiment exposing the front side and back side of a GaAs$(001)$ wafer to the ion beam clarifies its origin and proves that the ripples align to the Ga dimer rows. As the direction of Ga dimer rows rotates by 90{\deg} on the back side, the orientation of the ripples also rotates by 90{\deg} to $[110]$. We discuss the experimental results in view of a model where the pattern formation is driven by creation of vacancies and ad-atoms by the ion beam and their diffusion, which is linked to the direction of dimers on the surface.

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Martin Engler, Tomáš Škereň, Stefan Facsko. 2016-11-21. Nano patterns self-aligned to Ga dimer rows on GaAs surfaces. https://arxiv.org/abs/1611.06836

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