Single electron charging and transport in silicon rich oxide

Single electron charging and single electron tunnelling effects were observed in silicon rich oxide (SRO). The devices used in this study have an Al/SRO/Si metal-oxide-semiconductor-like structure, where the SRO layer was deposited using low pressure chemical vapour deposition. Two types of Si nanodots (NDs), interface NDs and bulk NDs, were identified by transmission electron microscopy measurements. Under electric field, charges from the Si substrate are transferred into the interface NDs that locate at the interface, and each interface ND traps only one carrier. As the voltage increases, conduction paths between the Al electrode and the silicon substrate are formed, and the conduction of electrons is via sequential tunnelling through the bulk NDs. Due to the Coulomb blockade effect, only one electron tunnels on each nanodot at a specific electric field. The transport of the electrons through the Si nanodots is due to the Poole-Frenkel mechanism in the voltage regime studied.