Physical and electrical properties of Ge-implanted SiO[sub 2] films.

Metal–oxide–semiconductor structures with a Ge nanocrystal embedded in SiO[sub 2] films were fabricated by Ge[sup +] ion implantation and subsequent high-temperature annealing. The Raman spectra indicate the evidence of self-assembled Ge nanocrystals in the SiO[sub 2] films. The Ge size and its density were estimated to 3–5 nm and 1×10[sup 12]/cm[sup 2], respectively. Photoluminescence spectra showed a strong blue–violet band around 400 nm and a weak near-infrared band around 750 nm, respectively. The several implantation-induced deficient centers are believed to be responsible for the blue-light luminescence. Capacitance–voltage characteristics exhibit the flatband voltage shifts of 1.02 V after the electron injection into the SiO[sub 2]/Ge/SiO[sub 2] potential well. An anomalous leakage current was clearly observed in the current–voltage characteristics. The precise simulation of quantum electron transport in the SiO[sub 2] film indicates that the anomalous conduction is originated from resonant tunneling in the SiO[sub 2]/Ge/SiO[sub 2] double-well band structure. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]