Charging effects in silicon nanocrystals within SiO2 layers, fabricated by chemical vapor deposition, oxidation, and annealing

Abstract

Metal–insulator–semiconductor structures with a layer of silicon nanocrystals embedded within the SiO2 layer at a tunneling distance from a p-type silicon substrate and fabricated using chemical vapor deposition, oxidation, and annealing, exhibited charge trapping, determined from the capacitance–voltage (C–V) characteristics, which abruptly increased at fields above 2.5 MV/cm. Electrons or holes are trapped when biasing the structure into inversion or accumulation, respectively, and retention of trapped charge is demonstrated. The I–V characteristics exhibit an N-shaped form, indicating screening effects due to charging; an initial current spike, attributed to transient charging of nanocrystals, occurs at the same voltage causing abrupt C–V shift increase, with Fowler–Nordheim current rising at higher voltages. These structures are promising for memory device applications.