Single-Charge Tunneling in Codoped Silicon Nanodevices

Area of Science:

• Materials Science
• Nanotechnology
• Semiconductor Physics

Background:

• Moore's Law is nearing its limit due to shrinking transistor gate lengths.
• Dopant behavior is critical in nanoscale semiconductor devices, influencing transport properties.
• Random dopant distribution significantly impacts nanostructure performance.

Purpose of the Study:

• To investigate single-charge tunneling in codoped silicon nanodevices.
• To explore the role of quantum dots formed by codoping in silicon nanostructures.
• To demonstrate enhanced functionalities in codoped silicon devices.

Main Methods:

• Fabrication of codoped silicon-on-insulator (SOI) films with phosphorus (P) donors and boron (B) acceptors.
• Characterization of highly doped pn diodes for band-to-band tunneling (BTBT).
• Analysis of nanoscale SOI field-effect transistors (SOI-FETs) for single-electron tunneling (SET).

Main Results:

• Observed BTBT via quantum dots (QDs) in depletion layers of codoped pn diodes.
• Reported current peaks and Coulomb diamonds in codoped nanoscale SOI-FETs.
• Attributed these phenomena to SET via QDs in nanoscale channels.

Conclusions:

• Codoped silicon nanostructures exhibit quantum dot formation due to dopant distribution.
• Single-charge tunneling phenomena (BTBT and SET) are achievable in these codoped systems.
• The interplay between donors and acceptors in silicon nanostructures offers new avenues for device applications.