Brauns Matthias, Amitonov Sergey V, Spruijtenburg Paul-Christiaan, Zwanenburg Floris A
NanoElectronics Group, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500, AE Enschede, The Netherlands.
Institute of Science and Technology Austria, Am Campus 1, 3400, Klosterneuburg, Austria.
Sci Rep. 2018 Apr 9;8(1):5690. doi: 10.1038/s41598-018-24004-y.
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.
我们用钯制成的栅极取代了用于在硅中形成量子点的已有的铝栅极。我们用透射电子显微镜研究了铝栅极和钯栅极的形态。发现天然氧化铝在铝栅极周围形成，这可能导致无意量子点的形成。因此，我们报道了一种新颖的制造方法，该方法用原子层沉积生长的氧化铝取代铝及其天然氧化物，以钯取而代之。使用这种方法，我们展示了低无序栅极定义量子点的形成，这些量子点可以重复制造。此外，钯使我们能够进一步缩小栅极设计，使我们能够在仅包含两个栅极层的器件中的少电子 regime 中进行电子输运测量，这是一项重大的技术进步。钯栅极的引入是否能改善用铝栅极堆栈定义的电子和核自旋量子比特的优异结果还有待观察。
