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We do inelastic electrical tunneling spectroscopy (IETS) to provide information concerning the vibrational and excitational modes present in silicon dioxide and phonon modes of the electrodes, and of silicon dioxide in metal-oxide-silicon tunnel junction. We analyze the phonon spectra coming from different parts of the metal-oxide-semiconductor (MOS) junction: the aluminum gate, the SiO2 ultrathin film, and the silicon substrate. We compare the phonon modes for the (100) and (111) silicon orientations. We show that IETS can reveal the modifications of Si-SiO2 interface induced by electrical stresses. After a constant voltage stress, the silicon longitudinal phonon modes are significantly shifted in energy, while the transversal phonon modes stay unaffected. Interface healing after annealing is also observed by IETS. These features make IETS a useful tool for MOS reliability studies.

We describe an easy to build inelastic electron tunneling spectrometer, controlled by a computer, to analyze and characterize metal–oxide–semiconductor (MOS) devices. The method, material, and circuit are also described. Typical inelastic electron tunneling spectra obtained from a MOS tunnel junction with various degrees of nonlinear conductance–voltage behavior are presented. Our results suggest that such a spectrometer has appropriate resolution (4 mV of full width half maximum) and suitable signal-to-noise ratio to clearly identify the electrode and insulator vibrational modes. Results are reported on aluminum gate 2.1 nm thick oxide devices fabricated on n-type (111) silicon substrates.

The inelastic electron tunnelling spectroscopy (IETS) technique is performed to provide information concerning the vibrational and excitational modes present in MOS tunnelling junctions (molecular species present in silicon dioxide and phonon modes of both silicon substrate and silicon dioxide). The first relevant structures of silicon substrate phonons are investigated in both (1 1 1) and (1 0 0) orientations for the first time. The separated peaks obtained after deconvolution are identified and compared with literature data for both silicon orientations. The IET spectrum of ultra-thin silicon dioxide is also obtained though this spectrum is more difficult to detect. Finally, two different technologies of manufacturing MOS tunnelling junctions are compared.

Fowler–Nordheim current in Si-poly (n+)-SiO2–Si(p) structures, with an oxide thickness varying between 3 and 12 nm, has been measured and numerically computed with the exact electric field in the oxide, the field dependence of the barrier shape with the image force, and the temperature effects. The fit of the experimental data leads to an accurate determination of the electron affinity difference and the barrier height at the emitting Si–poly (n+)-gate-electrode–oxide interface. The evolution of these two parameters with temperature is discussed in relation with the oxide thickness.

The variations with temperature of the Fowler–Nordheim (FN) emission in metal–oxide–semiconductor structures when the injecting electrode is the degenerate polysilicon gate (n+) are investigated. The temperature dependence of the electron affinity difference Φ between Si and SiO2 and of the barrier height Φb for three oxide thicknesses (5, 7, and 12 nm) are analyzed. The results are numerically derived from the exact integral expression of the FN current as functions of temperature varying from 25 to 300 °C. The variation with temperature of both the obtained Φ and dΦ/dT parameters at the polysilicon (n+)–oxide barrier are discussed with respect to the literature data.

Tunneling Fowler–Nordheim bidirectional electron injections were performed on a metal–oxide–silicon capacitor under constant voltage, and the study of generated defects behavior was investigated. It was found that defects generated within the oxide are of the same physical nature and are mainly composed of neutral traps. The charge and discharge of these traps depend on the oxide field polarity. At the oxide–silicon interface, the saturation of interface state generation is maintained by the alternate change of the stress field polarity. This saturation is linked to the Si−δ–H+δ or other Si−δ–A+δ polar bonds at the silicon/oxide interface.

Irradiation effects on the electrical characteristics under high field stress of nitrided and non-nitrided very thin silicon oxide films are studied. The generation of new electron traps during constant current stress is increased for irradiated samples. This enhancement is more significant for pure silicon dioxide when compared to nitrided oxide. Further, the correlation between charge to breakdown and traps generation rate during constant current injection is verified and remains valid after irradiation.

This work presents polarity effects during Fowler-Nordheim electric field stress on defect generation in thin silicon dioxide films and at the interface with the silicon. The results show a dissymmetry on interface state kinetic generation and the presence of a critical injected fluence at which the dissymmetry is reversed. For injected fluences lower than this critical charge, the density of interface states created under positive gate bias is higher than that generated under negative bias, and if the injected charge is higher than the critical fluence the dissymmetry is reserved. However, the net oxide positive charge generated under positive bias is always lower than that created under negative bias.

The influence of X-ray irradiation on the conduction properties and breakdown of silica layers less than 10 nm thick has been investigated. It has been found that these properties are not drastically affected, and that the X-ray irradiation induces a decrease of the defectiveness, as for much thicker layers.

The potential distribution across n+ polycristalline silicon (poly-Si)/SiO2/Si(p) structures, with an oxide layer thinner than 4 nm, was determined using a full quantum self-consistent model. When applied to capacitance–voltage measurements, it allows an accurate determination of the oxide thickness tox to be made. When applied to current–voltage measurements, in the Fowler–Nordheim regime, it leads to an accurate determination of the barrier height Φ at the interface between the emitting poly-Si gate electrode and the oxide, over a temperature range 20–250 °C. The results show a constant Φ(0 K) for 3 nm

In this paper, the influence of gamma irradiation (unbiased devices) on the electrical properties of Metal-Oxide-Semiconductor (MOS) devices with an ultra-thin silica layer N/sub 2/O-nitrided or not is investigated. Mainly electron trapping, defects generation and breakdown during electrical stress are studied.

Fowler–Nordheim (F.N.) tunneling of electrons from the gate into thin thermally grown SiO2 under high electrical field stress has been performed with polycrystalline Si‐SiO2‐Si capacitors and relaxation of both interface state densities and flat‐band voltage investigated during several months after F.N. stress at room temperature. It has been found that the relaxation behavior of surface states and positive charge densities follow fractional power laws in time.

High electrical stresses have been applied to n -MOS capacitors prepared following two thermal oxidation methods. The increase of the interface state density was investigated by means of a conductance method and incidentally by a quasi-static method. A threshold effect, possibly related to a Fowler-Nordheim injection, has been found in the increase of this density versus field stress. At high field stresses, a second conductance peak has been observed, which can be explained in terms of new interface states, rather than lateral nonuniformities.

MNS capacitors were submitted to a series of alternating voltage pulses, and measurements were performed at different stages of this cycling. The interface state parameters at the SiSi 3 N 4 interface were evaluated using the conductance method; the surface potential ψ S was obtained from a measurement of the high-frequency capacitance. Experimental results are explained by the formation, during cycling, of new fast surface states located at the SiSi 3 N 4 interface.

We review some of our recent experimental results on charge transport in organic nanostructures such as self-assembled monolayer and monolayers of organic semiconductors. We describe a molecular rectifying junction made from a sequential self-assembly on silicon. These devices exhibit a marked current-voltage rectification behavior due to resonant transport between the Si conduction band and the π molecule highest occupied molecular orbital of the π molecule. We discuss the role of metal Fermi level pinning in the current-voltage behavior of these molecular junctions. We also discuss some recent insights on the inelastic electron tunneling behavior of Si/alkyl chain/metal junctions.