Low-noise quantum dots in ultra-shallow Ge/SiGe heterostructures for prototyping hybrid semiconducting–superconducting devices
Abstract
Planar germanium is currently the only semiconducting platform where high-coherence spin qubits and proximity-induced superconductivity have each been demonstrated. Recent research into spin qubits in Ge/SiGe heterostructures has focused on increasing the thickness of the SiGe capping layer, reporting improvements in the electrostatic noise levels. Meanwhile, heterostructures with thinner capping layers remain rather unexplored, despite the potential advantages for proximity-induced superconductivity. Here, we study a Ge/SiGe heterostructure with a thin SiGe cap d≈4 nm and investigate its viability to host low-noise quantum dots. To keep the thermal budget compatible with superconducting layers, low-temperature oxide deposition processes were developed and implemented for the gate dielectrics. The charge noise level of the fabricated devices is estimated to be 1.8 ± 1.0 μeV/Hz, comparable to devices fabricated on shallow heterostructures (d∼20 nm) with high-temperature deposited oxides. Low charge noise levels, together with the straightforward integration of superconductors, make this heterostructure an attractive platform for prototyping hybrid semiconducting–superconducting devices.
Article Details
Journal Info
Applied Physics Letters
American Institute of Physics
Authors (18)
Maksim Borovkov
ISTA, Institute of Science and Technology Austria 1 , Am Campus 1, 3400 Klosterneuburg,
Yona Schell
Dina Sokolova
ISTA, Institute of Science and Technology Austria 1 , Am Campus 1, 3400 Klosterneuburg,
Kevin Roux
Paul Falthansl-Scheinecker
ISTA, Institute of Science and Technology Austria 1 , Am Campus 1, 3400 Klosterneuburg,
Giorgio Fabris
ISTA, Institute of Science and Technology Austria 1 , Am Campus 1, 3400 Klosterneuburg,
Devashish Shah
ISTA, Institute of Science and Technology Austria 1 , Am Campus 1, 3400 Klosterneuburg,
Jaime Saez-Mollejo
Rodolfo Previdi
ISTA, Institute of Science and Technology Austria 1 , Am Campus 1, 3400 Klosterneuburg,
Inas Taha
Aziz Genç
Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, Bellaterra, 08193, Barcelona, Catalonia Spain
Jordi Arbiol
Catalan Institute of Nanoscience and Nanotechnology − ICN2 (CSIC and BIST), Campus UAB, Bellaterra, Barcelona, Catalonia 08193, Spain
Stefano Calcaterra
Afonso De Cerdeira Oliveira
L-NESS, Physics Department, Politecnico di Milano 4 , via Anzani 42, 22100 Como,
Daniel Chrastina
Giovanni Isella
Anton Bubis
ISTA, Institute of Science and Technology Austria 1 , Am Campus 1, 3400 Klosterneuburg,
Georgios Katsaros