Dresden 2011 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 86: Quantum Dots: Growth and Characterization

HL 86.5: Talk

Friday, March 18, 2011, 11:15–11:30, FOE Anorg

Nanostructuring of silicon for the growth of site-controlled III/V quantum dots — •Muhammad Usman, Tariq Al Zoubi, Mohamed Benyoucef, and Johann Peter Reithmaier — Technische Physik, Institute of Nanostructure Technologies and Analytics, University of Kassel, Heinrich-Plett-Strasse 40, D-34132 Kassel, Germany

In order to localize the nucleation of III/V quantum dots during MBE growth, the silicon (100) substrate has been patterned with sub 100 nm holes. The processes involved in the nano-patterning of silicon, including electron beam lithography (EBL) and dry etching process, have been optimized. An anisotropic dry etching recipe based on SF6+CHF3 plasma has been used with optimal parameters in order to insure the precise transfer of holes defined on e-beam resist to the underlying silicon substrate. The control over the diameter of the patterned holes has been achieved through optimal EBL parameters including beam acceleration voltage, aperture size and exposure dose for single pixel dot. Arrays of holes with different periods from 1 μm down to 200 nm have been fabricated on silicon substrates. The diameter of the holes has been found to be unchanged for holes with periods of 1 μm, 750 nm and 500 nm, while a slight increase in the diameter for holes with period of 200 nm has been observed due to proximity effect. Preliminary results for the MBE growth of III/V quantum dots on nano-patterned silicon substrate have shown highly selective formation of quantum dots in the patterned holes with 1μm period.