Spin read-out in atomic qubits in an all-epitaxial three-dimensional transistor

Area of Science:

• Quantum Computing
• Materials Science
• Nanotechnology

Background:

• Topological error correction is crucial for universal quantum computers.
• Single-atom qubits in silicon require 2D arrays with vertical control electrodes.
• Precise vertical patterning of dopants is needed for 3D architectures.

Purpose of the Study:

• To demonstrate a 3D device architecture for single-atom qubits in silicon.
• To achieve high-fidelity spin readout of phosphorus dopant qubits.
• To enable precise interlayer alignment for vertically stacked qubit layers.

Main Methods:

• Utilized scanning tunneling microscope hydrogen resist lithography for 3D dopant patterning.
• Developed a vertically gated single-electron transistor architecture.
• Ensured minimal dopant diffusion during silicon encapsulation.

Main Results:

• Achieved <5 nm interlayer alignment accuracy in the 3D device.
• Demonstrated single-shot spin readout with 97.9% measurement fidelity.
• Fabricated a fully crystalline transistor using only silicon and phosphorus.

Conclusions:

• The 3D architecture is a viable pathway for scalable quantum computing.
• High-fidelity readout of phosphorus dopant qubits has been achieved.
• This method provides precise control over qubit placement and operation.