Palladium gates for reproducible quantum dots in silicon

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.

References in corpus (38)

• Quantum Computation with Quantum Dots
• Spins in few-electron quantum dots
• Electron transport through double quantum dots
• Silicon Quantum Electronics
• An addressable quantum dot qubit with fault-tolerant control fidelity
• A Two Qubit Logic Gate in Silicon
• A single-atom electron spin qubit in silicon
• Single-shot readout of an electron spin in silicon
• Storing quantum information for 30 seconds in a nanoelectronic device
• A CMOS silicon spin qubit
• High-fidelity readout and control of a nuclear spin qubit in silicon
• Excitation Spectra of Circular Few-Electron Quantum Dots
• Quantum transport in carbon nanotubes
• Scalable gate architecture for densely packed semiconductor spin qubits
• Singlet-triplet spin blockade and charge sensing in a few-electron double quantum dot
• Electron-hole symmetry in a semiconducting carbon nanotube quantum dot
• A fault-tolerant addressable spin qubit in a natural silicon quantum dot
• Electrically controlling single spin qubits in a continuous microwave field
• Pauli-Spin-Blockade Transport through a Silicon Double Quantum Dot
• Pauli Spin Blockade in a Highly Tunable Silicon Double Quantum Dot
• Charge sensing and controllable tunnel coupling in a Si/SiGe double quantum dot
• Pauli Spin Blockade of Heavy Holes in a Silicon Double Quantum Dot
• Spin states of the first four holes in a silicon nanowire quantum dot
• Pauli spin blockade in undoped Si/SiGe two-electron double quantum dots
• Observation of the single-electron regime in a highly tunable silicon quantum dot
• Dispersively detected Pauli Spin-Blockade in a Silicon Nanowire Field-Effect Transistor
• Single-electron quantum dot in Si/SiGe with integrated charge-sensing
• Gate-sensing coherent charge oscillations in a silicon field-effect transistor
• Resonant tunnelling features in the transport spectroscopy of quantum dots
• Electrostically defined few-electron double quantum dot in silicon
• Single-hole tunneling through a two-dimensional hole gas in intrinsic silicon
• High-fidelity adiabatic inversion of a ${}^{31}\mathrm{P}$ electron spin qubit in natural silicon
• Charge Sensing in Intrinsic Silicon Quantum Dots
• Passivation and characterization of charge defects in ambipolar silicon quantum dots
• A fabrication guide for planar silicon quantum dot heterostructures
• Double quantum dot with tunable coupling in an enhancement-mode silicon metal-oxide semiconductor device with lateral geometry
• Ambipolar quantum dots in intrinsic silicon
• Depletion-mode Quantum Dots in Intrinsic Silicon

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• Scaling silicon-based quantum computing using CMOS technology: State-of-the-art, Challenges and Perspectives
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• Probing single electrons across 300 mm spin qubit wafers
• Spin lifetime and charge noise in hot silicon quantum dot qubits
• A flexible design platform for Si/SiGe exchange-only qubits with low disorder
• Single-spin qubits in isotopically enriched silicon at low magnetic field
• Tunable coupling and isolation of single electrons in silicon metal-oxide-semiconductor quantum dots
• Coherent control of electron spin qubits in silicon using a global field
• Fabrication process and failure analysis for robust quantum dots in silicon
• Role of electron and ion irradiation in a reliable lift-off process with e-beam evaporation and a bilayer PMMA resist system
• Single-charge occupation in ambipolar quantum dots
• Tailoring potentials by simulation-aided design of gate layouts for spin qubit applications
• Integration of Cobalt Ferromagnetic Control Gates for Electrical and Magnetic Manipulation of Semiconductor Quantum Dots