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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.

The Fowler–Nordheim (FN) current in Si-poly (n + )-SiO 2 –Si(p) structures was measured and computed numerically using the complete integral equation taking into account the temperature, the flat-band voltage changes, the effective masses and the field dependence of the barrier shape with the image force. The fit of the experimental data allows an accurate determination of the electron affinity difference ( Φ ) and the barrier height ( Φ B ) at the emitting Si-poly(n + ) gate electrode–oxide interface. The correlation between the temperature changes of these two parameters and the oxide thickness is discussed.

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.

Fowler-Nordheim tunneling injections were performed, from the gate, or from the substrate, in P-type metal oxide semiconductor capacitors with polysilicon gates in both wet and dry oxides. When the injection was from the gate, trapped holes, as well as negative and anomalous positive charges were created and it was possible to determine their amplitude and their centroid. When the injection was from the substrate, only negative and anomalous positive charges were created, but the determination of the centroids was not always possible since the positive charge appears to be located at both interfaces.

The oxide positive charge and the interface-state formation caused by a negative gate bias in a polycrystalline silicon gate-oxide-semiconductor capacitor versus injecting temperature in the range of 77–400 K is studied. It is found that the generation of both interface-states and oxide charge is temperature independent which indicates that the motion of each mobile species (as the hydrogen-related species) must be excluded. The formation of interface-states is linked to the break of SiSi or SiO distorted bonds at the Si SiO 2 interface, and the generation of the oxide positive charge to the electron-emission from pre-existing or created neutral traps.

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 possibilities of tunneling spectroscopy in metal-oxide-degenerate silicon with a very thin oxide layer have been studied at low temperature by measuring the first and second derivatives of the current-voltage characteristics. Silicon phonon structures are easily detectable whereas high level features induced by molecular vibrations are hardly seen. The aim of this paper is to show that the main difficulty lies in the metal-oxide-semiconductor junction band structure itself.

The paper deals with porous Si (PSi) samples, prepared with different parameters (substrate, current density, solution, etc.) of anodization and anodic oxidation. The porosity of samples varied between 36 and 78%, their thickness was 1–5 p.m. The samples were studied in six laboratories using complementary methods. The spectra of elastic reflection coefficients r e (E p ) are characteristic of the composition and they are affected by the structure of the surface layer. They were measured with a retarding field analyser using spectrometer correction and deduced from the elastic peak versus E p primary energy. The r e (E p ) showed a dramatic decrease in the 50–100 eV range with H adatoms on the surface, produced by HF treatment. It is caused by attenuation and multiple elastic reflections of electrons on the porous surface with H adatoms. An oxidized sample showed a contrary effect, which can be explained by the elastic reflection cross-sections of Si and O in this low energy range. Valence band XPS spectra were measured with a KRATOS XSAM 800 analyser. They showed changes with HF treatment and porous structure. To avoid difficulties with STM due to the oxide, the surface topography was mapped by atomic force microscopy, resulting in 0.3–0.9 nm roughness on samples of 36% porosity.

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.

Tunnelling phenomena were studied in two kinds of specimens: samples A, essentially metal—silicon junctions, featured a thin silicon oxide transition layer; samples B were prepared by the anodization of silicon in pure water. I, dI/dV and d2I/dV2vs. V curves were obtained at liquid helium temperature. For both specimens, the general shapes of the curves were in agreement with the theoretical prediction. Phonon fine structure was obtained. Moreover, for samples A, a zero-bias anomaly phenomenon, indicating the presence of metal particles in the oxide, as well as other structures, due to traps, were observed. The absence of such structures and of a zero-bias anomaly for samples B and the appearance of phonon structures, in spite of the considerably smaller amount of doping, are indications of a good quality oxide. This was in accordance with capacitance measurements made on thicker oxide obtained by the same process. These experiments show that inelastic electron tunnelling spectroscopy can be used as a valuable tool for the study of very thin silicon oxide layers in electron devices.

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.

An insulating layer is produced on aluminum by glow discharge in CF4. This substrate, used as the insulator of metal-insulator-metal diodes is characterized by Inelastic Electron Tunneling Spectroscopy as an aluminum trifluoride AlF3. The adsorption of ammonia, benzylamine. formic and propiolic acid on this substrate is investigated. A comparison between spectra of samples obtained on this insulator and on alumina for the same dopant molecules shows significant differences which are interpreted as revealing an enhanced Lewis acidity of AlF3 relative to Al2O3, determined — at least in part — by an enhanced electronegativity of surface Al+ cations of AlF3.