Charge retention characteristics of silicon nanocrystal layers by ultrahigh vacuum atomic force microscopy

The nanoscale charge retention characteristics of both electrons and holes in SiO2 layers containing silicon nanocrystals were investigated with ultrahigh vacuum conductive-tip noncontact atomic force microscopy. The results revealed much longer hole retention time (e.g., >1 day) than that of electrons (e.g., ∼1 h). A three-dimensional electrostatic model was developed for charge quantification and analysis of charge dissipation. Based on the superior retention characteristics of holes, a p-channel nanocrystal memory working with holes is suggested to be an interesting choice in improving data retention or in further device scaling.