Experimental analysis of the stability of electrostatic bits for assisted nano-assembly

Scanning probe microscopy(SPM)-based nanolithography with injected charges into layered electrets, such as silicon dioxide (SiO₂) and silicon nitride, is a promising tool with far-reaching applications, such as controlled nano-assembly of macro-molecules and data storage. Despite its potential, some practical limitations exist. This paper describes an experimental investigation of the process of charging and charge dissipation in SiO₂ using an AFM probe tip and surface potential (Kelvin probe) microscopy. The stability of charge bits on hexamethyl disilazane(HMDS)-treated SiO₂ under low dielectric constant liquids, fluorocarbon, and benzene has been demonstrated. Results from a numerical simulation of a theoretical charging model, in which the charge traps are assumed to be localized on the silicon/SiO₂ interface, are also presented. The charge transport mechanism considered is modified Fowler–Nordheim tunneling.