Ultra-dense phosphorous delta-layer grown into silicon from PH3 molecular precursors
Phosphorous δ-doping layers were fabricated in silicon by PH3 deposition at room temperature, followed by low-temperature Si epitaxy. Scanning tunneling microscope images indicate large H coverage, and regions of c(2x2) structure. Hall data imply full carrier activation with mobility <40cm2/Vs when the surface coverage is <0.2 ML. Conductivity measurements show a ln(T) behavior at low temperatures, characteristic of a high-density two-dimensional conductor. Possible future applications to atom-scale electronics and quantum computation are briefly discussed.
T.-C. Shen, J.-Y. Ji, M. A. Zudov, R.-R. Du, J. S. Kline, J. R. Tucker, “Ultra-dense phosphorous delta-layer grown into silicon from PH3 molecular precursors,” Appl. Phys. Lett. 80, 1580-1582 (2002).