Fowler-Nordheim tunneling current oscillations at metal/oxide/Si interfaces

Fowler-Nordheim tunnelling current oscillations are used to investigate two metal/oxide/Si interfaces: n(+) polysilicon/oxide and oxide/p-Si interfaces on the same samples for p-Si substrate metal-oxide-semiconductor devices. Electron injection from the p-Si substrate is facilitated by the application of visible light during the I-V measurement in order to create and inject sufficient carriers into the SiO2 conduction band. We compare the interfaces of thermal with rapid thermal silicon oxides prepared with nitrogen. We find that these two processes yield 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 be approximated at 2.80+/-0.1 eV. (C) 1997 American Institute of Physics.