Uniform Spin Qubit Devices in an All-Silicon 300 mm Integrated Process

TL;DR

This paper demonstrates highly uniform and tunable silicon-based spin qubit devices fabricated on a 300mm wafer, enabling scalable quantum computing with improved device consistency and control.

Contribution

It introduces an all-silicon, lithographically flexible fabrication process for uniform spin qubits with integrated polycrystalline silicon gates on a large-scale wafer.

Findings

Achieved low-disorder Si/SiO₂ with high Hall mobility.

Demonstrated reproducible interdot coupling over 2 decades.

Showed spin manipulation and single-shot readout with valley splitting.

Abstract

Larger arrays of electron spin qubits require radical improvements in fabrication and device uniformity. Here we demonstrate excellent qubit device uniformity and tunability from 300K down to mK temperatures. This is achieved, for the first time, by integrating an overlapping polycrystalline silicon-based gate stack in an 'all-Silicon' and lithographically flexible 300mm flow. Low-disorder Si/SiO$_2$ is proved by a 10K Hall mobility of $1.5 \cdot 10^4$ $cm^2$/Vs. Well-controlled sensors with low charge noise (3.6 $\mu$eV/$\sqrt{\mathrm{Hz}}$ at 1 Hz) are used for charge sensing down to the last electron. We demonstrate excellent and reproducible interdot coupling control over nearly 2 decades (2-100 GHz). We show spin manipulation and single-shot spin readout, extracting a valley splitting energy of around 150 $\mu$eV. These low-disorder, uniform qubit devices and 300mm fab integration pave the way for fast scale-up to large quantum processors.