Silicon (Si) Substrate

Superconducting Materials

The Foundation of Most Quantum Chips

Non-superconducting — dielectric substrate

Silicon (Si) Substrate

The Foundation of Most Quantum Chips

Role in quantum circuits

Substrate / foundation for depositing superconducting thin films and qubit circuits

Why it matters

High-resistivity intrinsic silicon is a common substrate because semiconductor

fabrication techniques are directly compatible. It enables patterning of qubits using electron-beam and optical lithography at scale, including double-sided qubit chip fabrication workflows.

Key facts

• Dielectric constant ~11.7; extremely well-characterised

• Float-zone (intrinsic) Si has very low impurity levels

• Compatible with standard cleanroom microfabrication tools

• Loss tangent must be carefully managed at millikelvin temperatures

• Supports double-sided 3-inch wafer fabrication workflows