Industrial 300$\,$mm wafer processed spin qubits in natural silicon/silicon-germanium

TL;DR

This paper demonstrates the fabrication of silicon spin qubits on a 300mm industrial wafer process line using natural silicon, achieving high coherence, fast control, and reproducibility crucial for scalable quantum computing.

Contribution

It presents the first fully industrial 300mm wafer process fabrication of natural silicon spin qubits with high performance and reproducibility, advancing scalable quantum processor development.

Findings

Charge noise below 2 μeV/√Hz

Spin relaxation times over 1 second

Single qubit gate fidelities above 99%

Abstract

The realisation of an universal quantum computer will require the operation of thousands to millions of qubits. The possibility of using existing industrial semiconductor fabrication techniques and infrastructure for up-scaling and reproducibility makes silicon based spin qubits one of the most promising platforms to achieve this goal. The implementation of the up to now largest semiconductor based quantum processor was realized in a silicon/silicon-germanium heterostructure known for its low charge noise, long qubit coherence times and fast driving speeds, but the high structural complexity creates challenges for industrial implementations. Here we demonstrate quantum dots hosted in a natural Si/SiGe heterostructure fully fabricated by an industrial 300$\,$mm semiconductor wafer process line from heterostructure growth to Co micromagnet monolithic integration. We report charge noise values below 2$\,\mathrm{\mu eV/\sqrt{Hz}}$, spin relaxation times of over 1$\,$s and coherence times $T_2^*$ and $T_2^H$ of 1$\,\mathrm{\mu s}$ and 50$\,\mathrm{\mu s}$ respectively, for quantum wells grown using natural silicon. Further, we achieve Rabi frequencies up to 5$\,$MHz and single qubit gate fidelities above 99$\,\%$. In addition to scalability, the high reproducibility of the 300$\,$mm processes enables the deterministic study of qubit metric dependencies on process parameters, which is essential for optimising qubit quality.