Device fabrication and transport measurements of FinFETs built with $^{28}$Si SOI wafers towards donor qubits in silicon

TL;DR

This paper demonstrates the fabrication and electrical characterization of FinFET devices using isotopically purified silicon-28 on insulator, advancing the development of donor-based spin qubits in silicon for quantum computing.

Contribution

It introduces a FinFET fabrication process compatible with single-ion implantation and electrical spin readout in isotopically purified silicon-28, suitable for quantum bit applications.

Findings

Successful fabrication of FinFETs on 28-SOI wafers.

Electrical transport measurements at 0.3 K show promising device performance.

Compatibility with single-ion implant detection demonstrated.

Abstract

We report fabrication of transistors in a FinFET geometry using isotopically purified silicon-28 -on-insulator (28-SOI) substrates. Donor electron spin coherence in natural silicon is limited by spectral diffusion due to the residual $^{29}$Si nuclear spin bath, making isotopically enriched nuclear spin-free $^{28}$Si substrates a promising candidate for forming spin quantum bit devices. The FinFET architecture is fully compatible with single-ion implant detection for donor-based qubits, and the donor spin-state readout through electrical detection of spin resonance. We describe device processing steps and discuss results on electrical transport measurements at 0.3 K.