Quantum Dot Arrays in Silicon and Germanium

Abstract

Electrons and holes confined in quantum dots define an excellent building block for quantum emergence, simulation, and computation. In order for quantum electronics to become practical, large numbers of quantum dots will be required, necessitating the fabrication of scaled structures such as linear and 2D arrays. Group IV semiconductors contain stable isotopes with zero nuclear spin and can thereby serve as excellent host for spins with long quantum coherence. Here we demonstrate group IV quantum dot arrays in silicon metal-oxide-semiconductor (SiMOS), strained silicon (Si/SiGe) and strained germanium (Ge/SiGe). We fabricate using a multi-layer technique to achieve tightly confined quantum dots and compare integration processes. While SiMOS can benefit from a larger temperature budget and Ge/SiGe can make ohmic contact to metals, the overlapping gate structure to define the quantum dots can be based on a nearly identical integration. We realize charge sensing in each platform, for the first time in Ge/SiGe, and demonstrate fully functional linear and two-dimensional arrays where all quantum dots can be depleted to the last charge state. In Si/SiGe, we tune a quintuple quantum dot using the N+1 method to simultaneously reach the few electron regime for each quantum dot. We compare capacitive cross talk and find it to be the smallest in SiMOS, relevant for the tuning of quantum dot arrays. These results constitute an excellent base for quantum computation with quantum dots and provide opportunities for each platform to be integrated with standard semiconductor manufacturing.

Main text: 8 pages, 6 figures. Supporting Info: 5 pages, 3 figures

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Cited by in corpus (64)

• Semiconductor Spin Qubits
• Universal control of a six-qubit quantum processor in silicon
• A four-qubit germanium quantum processor
• The germanium quantum information route
• Universal quantum logic in hot silicon qubits
• CMOS-based cryogenic control of silicon quantum circuits
• A single-hole spin qubit
• Review of performance metrics of spin qubits in gated semiconducting nanostructures
• Low-frequency spin qubit detuning noise in highly purified ${}^{28}$Si/SiGe
• Probing quantum devices with radio-frequency reflectometry
• Simultaneous single-qubit driving of semiconductor spin qubits at the fault-tolerant threshold
• Atomic fluctuations lifting the energy degeneracy in Si/SiGe quantum dots
• A flexible design platform for Si/SiGe exchange-only qubits with low disorder
• Single-electron double quantum dots in bilayer graphene
• Automated tuning of double quantum dots into specific charge states using neural networks
• The SpinBus Architecture: Scaling Spin Qubits with Electron Shuttling
• Sweet-spot operation of a germanium hole spin qubit with highly anisotropic noise sensitivity
• Shuttling an electron spin through a silicon quantum dot array
• Charge detection in an array of CMOS quantum dots
• Low charge noise quantum dots with industrial CMOS manufacturing
• Spin relaxation benchmarks and individual qubit addressability for holes in quantum dots
• Silicon quantum dot devices with a self-aligned second gate layer
• A 300 mm foundry silicon spin qubit unit cell exceeding 99% fidelity in all operations
• Semiconductor materials stacks for quantum dot spin qubits
• A two-dimensional array of single-hole quantum dots
• Longitudinal and transverse electric field manipulation of hole spin-orbit qubits in one-dimensional channels
• Electrical control of uniformity in quantum dot devices
• Interplay of charge noise and coupling to phonons in adiabatic electron transfer between quantum dots
• Hybrid superconductor-semiconductor systems for quantum technology
• Probing the Spatial Variation of the Inter-Valley Tunnel Coupling in a Silicon Triple Quantum Dot
• Bounds to electron spin qubit variability for scalable CMOS architectures
• Wafer-scale low-disorder 2DEG in ${}^{28}$Si/SiGe without an epitaxial Si cap
• Charge-noise induced dephasing in silicon hole-spin qubits
• Topology detection in cavity QED
• CMOS Quantum Computing: Toward A Quantum Computer System-on-Chip
• Majorana zero modes in gate-defined germanium hole nanowires
• Autonomous estimation of high-dimensional Coulomb diamonds from sparse measurements
• A quantum dot in germanium proximitized by a superconductor
• Electrical operation of hole spin qubits in planar MOS silicon quantum dots
• Interplay of exchange and superexchange in triple quantum dots
• Single-electron occupation in quantum dot arrays at selectable plunger gate voltage
• Long-range electron-electron interactions in quantum dot systems and applications in quantum chemistry
• Tunable interdot coupling in few-electron bilayer graphene double quantum dots
• Vanishing Zeeman energy in a two-dimensional hole gas
• Coupled vertical double quantum dots at single-hole occupancy
• Extended Hubbard model describing small multi-dot arrays in bilayer graphene
• Voltage-controlled Hubbard spin transistor
• Flying Spin Qubits in Quantum Dot Arrays Driven by Spin-Orbit Interaction
• Local laser-induced solid-phase recrystallization of phosphorus-implanted Si/SiGe heterostructures for contacts below 4.2 K
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• Quantification of the heavy-hole--light-hole mixing in two-dimensional hole gases
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• High fidelity TiN processing modes for multi-gate Ge-based quantum devices
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