Regensburg 2019 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 25: Group IV (other than C): Si/Ge/SiC

HL 25.8: Vortrag

Mittwoch, 3. April 2019, 11:30–11:45, H33

Ordered Si nanopillar arrays with alternating diameters by metal-assisted chemical etching — •Michael Kismann, Thomas Riedl, Xia Wu, Bertram Schwind, Thorsten Wagner, and Jörg K.N. Lindner — Paderborn University, 33098 Paderborn, Germany

Ordered Si nanopillar arrays have a great potential for e.g. photonic, sensing and electronic devices. In the present contribution, we employ nanosphere lithography combined with metal-assisted chemical etching (MACE), which permits the fabrication of well ordered Si nanopillar arrays on large areas. Compared with conventional fabrication techniques such as optical lithography combined with deep RIE or CVD our approach is more cost-effective and enables realization of high aspect ratio structures. Moreover, as a new feature of MACE we demonstrate the formation of Si nanopillars with alternating diameters by variation of the etch solution composition, which is accomplished by varying the HF/H₂O₂ ratio. In this way single and multiple necks can be formed in each nanopillar. By controlled oxidation in water vapour we obtain nanoscale Si inclusions surrounded by an amorphous SiO₂ shell. The morphology and structure of these pillar arrays are analyzed by SEM and TEM, complemented by optical measurements and band structure calculations. The obtained necked Si pillar morphologies are attractive for vertical nanopillar FETs and vertical tunneling FETs. In addition, they are of interest for thermoelectric generators because of the strongly reduced thermal conductivity in the nanostructures and the possibility of resonant tunneling through the SiO₂ necks.