99.992 % $^{28}$Si CVD-grown epilayer on 300 mm substrates for large scale integration of silicon spin qubits

TL;DR

This paper reports the growth of highly pure $^{28}$silicon epitaxial layers on 300 mm substrates, enabling large-scale integration of silicon spin qubits with high isotopic purity and CMOS-compatible quality.

Contribution

It demonstrates the successful fabrication of $^{28}$silicon epilayers with over 99.992% purity on large 300 mm substrates, suitable for quantum computing applications.

Findings

Achieved >99.992% isotopic purity in $^{28}$silicon epilayers

Epilayers meet CMOS-quality standards for large-scale integration

Compatible with existing 300 mm silicon fabrication processes

Abstract

Silicon-based quantum bits with electron spins in quantum dots or nuclear spins on dopants are serious contenders in the race for quantum computation. Added to process integration maturity, the lack of nuclear spins in the most abundant $^{28}$silicon isotope host crystal for qubits is a major asset for this silicon quantum technology. We have grown $^{28}$silicon epitaxial layers (epilayers) with an isotopic purity greater than 99.992 % on 300mm natural abundance silicon crystals. The quality of the mono-crystalline isotopically purified epilayer conforms to the same drastic quality requirements as the natural epilayers used in our pre-industrial CMOS facility. The isotopically purified substrates are now ready for the fabrication of silicon qubits using a state-of-the-art 300 mm Si CMOS-foundries equipment and processes