A hole spin qubit in a fin field-effect transistor above 4 kelvin

Abstract

The greatest challenge in quantum computing is achieving scalability. Classical computing previously faced a scalability issue, solved with silicon chips hosting billions of fin field-effect transistors (FinFETs). These FinFET devices are small enough for quantum applications: at low temperatures, an electron or hole trapped under the gate serves as a spin qubit. Such an approach potentially allows the quantum hardware and its classical control electronics to be integrated on the same chip. However, this requires qubit operation at temperatures above 1 K, where the cooling overcomes heat dissipation. Here, we show that silicon FinFETs can host spin qubits operating above 4 K. We achieve fast electrical control of hole spins with driving frequencies up to 150 MHz, single-qubit gate fidelities at the fault-tolerance threshold, and a Rabi oscillation quality factor greater than 87. Our devices feature both industry compatibility and quality, and are fabricated in a flexible and agile way that should accelerate further development.

Compilation and scaling strategies for a silicon quantum processor with sparse two-dimensional connectivity

“…However, the fact that holes exhibit larger spin-orbit coupling when compared to electron spins would allow for all-electrical control via the QD gates at relatively fast Rabi frequencies of up to 150 MHz via electric-dipole spin resonance (EDSR) [54]. We note that full control over the Bloch sphere of hole spins via X and Y rotations has been recently demonstrated with fidelities in excess of 99% [53].…”

“…ESR allows two axis control (X and Y gates) by controlling the duration of the gate voltage pulses and the phase of the microwave excitation. Implementing the proposed architecture with hole-spin qubits, on the other hand, would result in shorter coherence times (T * 2 > 250 ns) [52,53]. However, the fact that holes exhibit larger spin-orbit coupling when compared to electron spins would allow for all-electrical control via the QD gates at relatively fast Rabi frequencies of up to 150 MHz via electric-dipole spin resonance (EDSR) [54].…”

Monolithic Integration of Quantum Resonant Tunneling Gate on a 22nm FD-SOI CMOS Process

“…That said, characterizing the performance of charge and spin qubits under non-ideal conditions is an active area of research. Recently, Ramsey decay (T 2 ) of 75 ns and 200 ns was measured for a spin qubit at 3.5 K and 1 K respectively 23 . Once performance trade-offs are understood and experimentally verified, the scientific community is likely to converge on a "sweet spot" temperature setting that addresses the challenges in scaling and integration with an acceptable qubit fidelity.…”

Fully tunable longitudinal spin-photon interactions in Si and Ge quantum dots

“…I of [66]. Importantly, the amplitude of γ γ γ L is large and fully tunable by an external electric field E. By simulating long quantum dots in Ge/Si core/shell nanowires [9,21,68,69] and in square Si finFETs [23][24][25], we observe that large coupling strengths |γ γ γ GeO [22,[73][74][75], where the lower symmetry of the cross-section permits to completely turn off the SOI at finite values of E [11] (marked with a triangle). We also examine a quantum dot in strained planar Ge/SiGe heterostructures, an architecture that holds much promise for scaling up quantum computers [17][18][19].…”

“…Spin qubits in silicon (Si) and germanium (Ge) quantum dots are frontrunner candidates to process quantum information [1][2][3][4][5][6]. Hole spin qubits hold particular promise because of their large and fully tunable spin-orbit interactions (SOI) [7][8][9][10][11][12][13][14][15], enabling ultrafast all-electrical gates at low power [16][17][18][19][20][21][22][23][24][25], and because of their resilience to hyperfine noise even in natural materials [26][27][28][29][30][31]. In current quantum processors, engineering long-range interactions of distant qubits remains a critical challenge.…”