Si nanocrystal based memories: Effect of the nanocrystal density

Si nanocrystals designed for memory applications were prepared in a layered arrangement by using a SiOx/SiO2 multilayer structure with a variation of the stoichiometry parameter x from 0.9 to 1.63. The stoichiometry of the SiOx layers is controlled by adjusting the oxygen pressure during the growth which influences the resulting area density of the Si nanocrystals after high temperature annealing from around (2.8-0.93)x10(12)/cm(2). The tuning of the Si nanocrystal area density in the layers is demonstrated by transmission electron microscopy as well as by comparison of capacitance-voltage and photoluminescence measurements. The influence of the nanocrystal density on the charge behavior is demonstrated and discussed. Our method realizes a simple way to control the area density by maintaining equally sized nanocrystals, that gives unique possibilities to study the influence of the nanocrystal density on the electrical properties. (c) 2006 American Institute of Physics.