FOWLER-NORDHEIM TUNNELING CURRENT OSCILLATIONS AT METAL OXIDE/SI INTERFACES/

Fowler-Nordheim tunnelling current oscillations are used to investigat e two metal/oxide/Si interfaces: n(+) polysilicon/oxide and oxide/p-Si interfaces on the same samples for p-Si substrate metal-oxide-semicon ductor devices. Electron injection from the p-Si substrate is facilita ted by the application of visible light during the I-V measurement in order to create and inject sufficient carriers into the SiO2 conductio n band. We compare the interfaces of thermal with rapid thermal silico n oxides prepared with nitrogen. We find that these two processes yiel d the same quality of interfaces. An analysis of the magnitude of the current oscillations indicates that the oxide/Si interface is superior to the polysilicon/oxide interface. Oxide thicknesses are determined from the oscillations at each interface for devices fabricated on the same wafer, and the requirement of constant film thickness enables the (uncertain) value of the barrier at the p-Si injecting electrode to b e approximated at 2.80+/-0.1 eV. (C) 1997 American Institute of Physic s.