Sequential reduction of the silicon single-electron transistor structure to atomic scale.

Area of Science:

• Solid-state physics
• Quantum electronics
• Nanotechnology

Background:

• Fabricating single-electron transistors (SETs) with precisely controlled quantum dots is challenging.
• Existing methods often lack scalability and precise control over island size and dopant numbers.
• Understanding electron transport through individual dopants in silicon is crucial for quantum computing.

Purpose of the Study:

• To present a novel CMOS-compatible fabrication method for SETs using solitary dopants.
• To demonstrate controllable size reduction of silicon nanobridges for quantum confinement.
• To investigate electron transport phenomena through individual phosphorus dopants in silicon.

Main Methods:

• Utilized CMOS-compatible fabrication techniques.
• Employed sequential cycles of low-energy isotropic reactive ion etching for nanobridge size reduction.
• Analyzed electron transport using Coulomb blockade measurements and current stability diagrams.

Main Results:

• Achieved a single-electron transistor structure with extremely small islands formed by solitary phosphorus dopants.
• Demonstrated controllable reduction of nanobridge size, decreasing active dopants from hundreds to a few.
• Observed single-electron transport through three phosphorus atoms with a Coulomb blockade voltage of ~30 mV.

Conclusions:

• The developed fabrication method enables the creation of SETs with precisely controlled quantum dots.
• This technique facilitates the study of electron transport through individual dopants in silicon nanostructures.
• The method is adaptable for incorporating various impurities, offering pathways for advanced quantum devices.