Palladium gates for reproducible quantum dots in silicon Journal Article

Author(s): Brauns, Matthias; Amitonov, Sergey V; Spruijtenburg, Paul-Christiaan; Zwanenburg, Floris A
Article Title: Palladium gates for reproducible quantum dots in silicon
Affiliation IST Austria
Abstract: We replace the established aluminium gates for the formation of quantum dots in silicon with gates made from palladium. We study the morphology of both aluminium and palladium gates with transmission electron microscopy. The native aluminium oxide is found to be formed all around the aluminium gates, which could lead to the formation of unintentional dots. Therefore, we report on a novel fabrication route that replaces aluminium and its native oxide by palladium with atomic-layer-deposition-grown aluminium oxide. Using this approach, we show the formation of low-disorder gate-defined quantum dots, which are reproducibly fabricated. Furthermore, palladium enables us to further shrink the gate design, allowing us to perform electron transport measurements in the few-electron regime in devices comprising only two gate layers, a major technological advancement. It remains to be seen, whether the introduction of palladium gates can improve the excellent results on electron and nuclear spin qubits defined with an aluminium gate stack.
Keywords: Electronic devices; spintronics
Journal Title: Scientific Reports
Volume: 8
Issue 1
ISSN: 20452322
Publisher: Nature Publishing Group  
Date Published: 2018-04-09
Start Page: Article number: 5690
Copyright Statement: CC BY 4.0
Sponsor: This work is part of the research programme “Atomic physics in the solid state” with project number 14167, which is (partly) financed by the Netherlands Organisation for Scientific Research (NWO).
DOI: 10.1038/s41598-018-24004-y
Notes: The authors want to thank Joost Ridderbos and Wilfred van der Wiel for fruitful discussions. Tess Meijerink was so kind as to be of excellent support during the electron transport measurements. All authors want to express their gratitude to Hans Mertens and Rico Keim for technical support.
Open access: yes (OA journal)