Study of charge storage characteristics of memory devices embedded with metallic nanoparticles

The structural and electrical properties of thin silicon dioxide and hafnium oxide dielectric stacks with embedded gold nanoparticles obtained by electron-beam evaporation are reported. Transmission electron microscopy shows that the nanoparticles have a mean diameter of 2.6 nm and a sheet density of 3.3×1012 cm−2. High-frequency and quasi-static capacitance–voltage measurements of MOS capacitors reveal that charge injection and storage takes place in the nanoparticle dielectric stack at low gate voltages. Efficient charge trapping occurs only in the case of holes injected from the substrate. Programming and retention time measurements indicate that the fabricated nanoparticle dielectrics are attractive for low-voltage non-volatile memory applications.