Deterministic Shallow Dopant Implantation in Silicon with Detection Confidence Upper-Bound to 99.85% by Ion-Solid...

Area of Science:

• Solid State Physics
• Quantum Computing Materials
• Semiconductor Device Fabrication

Background:

• Single dopant atoms in silicon are crucial for classical and quantum devices.
• Group-V donors in purified silicon are promising for large-scale quantum computers.
• Existing methods require high-yield fabrication of near-surface dopant arrays.

Purpose of the Study:

• To demonstrate near-room-temperature, single 31P+ ion implantation in silicon.
• To achieve high-confidence single-ion detection for scalable dopant architectures.
• To assess the practical yield limitations in silicon device fabrication.

Main Methods:

• Utilized an on-chip detector electrode system with 70 eV RMS noise (approx. 20 electrons).
• Performed near-room-temperature implantation of single 14 keV 31P+ ions.
• Developed a physics model for ion-solid interaction to determine detection confidence.

Main Results:

• Achieved an unprecedented single-ion detection confidence upper-bound of 99.85 ± 0.02% for near-surface implants.
• Demonstrated a practical controlled silicon doping yield limit of 98.1% for devices with 6 nm gate oxide.
• Identified materials engineering factors, such as gate oxides, as primary yield limitations.

Conclusions:

• Deterministic single-ion implantation is a viable strategy for scalable dopant architectures in silicon.
• Reducing gate oxide thickness can improve doping yield, approaching the theoretical detection limit.
• This technique supports the development of advanced silicon-based quantum devices.