Charge storage characteristics of nonvolatile memories with chemically-synthesized and vacuum-deposited gold nanoparticles

• Memories with chemically-synthesized (CS) and vacuum-deposited (VD) Au-NPs studied.
• Chemical oxide formation on SiO2 layer of CS memories examined by EDS and UPS.
• Programming saturation of memories with VD Au-NPs explained by potential coupling.
• Low charge loss of memories with CS Au-NPs due to additional chemical oxide layer.

Carrier injection and charge loss characteristics of nonvolatile memories with chemically-synthesized (CS) and vacuum-deposited (VD) gold nanoparticles (Au-NPs) have been investigated. Compared to CS counterparts, the memories with VD Au-NPs exhibit a higher dot density of 3.77 × 1011 cm−2, leading to a larger memory window. Further, the energy from valence-band edge to vacuum level (EVB_vac) of tunneling oxide for the samples with CS and VD Au-NPs is found to be 9.04 and 9.85 eV respectively. The small EVB_vac value of the memories with CS Au-NPs is resulted from the formation of a thin chemical oxide (SiOx) on thermally-grown SiO2 tunneling layer during the chemically synthesized process, contributing to a slow erasing behavior. Besides, the programming of the memories with VD Au-NPs is saturated at high gate bias, which has been well-explained by the electrons induced potential coupling between Au-NPs. Superior data retention property and high temperature dependence of charge loss are observed for the memories with CS Au-NPs, which can be ascribed to the thick tunneling oxide layer by the additional SiOx film.