Effect of annealing environment on the memory properties of thin oxides with embedded Si nanocrystals obtained by low-energy ion-beam synthesis

Abstract

The effect of annealing in diluted oxygen versus inert environment on the structural and electrical characteristics of thin silicon dioxide layers with embedded Si nanocrystals fabricated by very low-energy silicon implantation (1 keV) is reported. Annealing in diluted oxygen increases the thickness of the control oxide, improves the integrity of the oxide and narrows the size distribution of the nanocrystals without affecting significantly their mean size (∼2 nm). Strong charge storage effects at low gate voltages and enhanced charge retention times are observed through electrical measurements of metal-oxide-semiconductor capacitors. These results indicate that a combination of low-energy silicon implants and annealing in diluted oxygen allows for the fabrication of improved low-voltage nonvolatile memory devices.