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Research describing the relationship between degradation and breakdown of ultrathin silicon dioxide is presented. In particular the effects of substrate hot hole injection are investigated.

The effect of hydrogen absorption on the bulk of amorphous SiO2 thin films is investigated.

The effects of thermal annealing on the optical and structural properties of Ge-doped SiO2 thin films have been studied. The films have been prepared through chemical vapor deposition (CVD) and flame hydrolysis deposition. Results indicate that thin films formed through CVD have inhomogeneous Ge distribution with Ge oxygen-deficient centers. However, the Ge distribution became uniform when the films were annealed at temperatures higher than 800 C. There was also a reduction in the number of oxygen-deficient centers when annealing was done in an O2 atmosphere.

Research was conducted to examine the microstructure, atomic density and electrical resistivity of reactively sputtered Ru-Si-O ternary films.The evolution of some of the properties upon heat treatment was analyzed within the framework of a ternary phase diagram from the Ru-Si-O system. Results suggest that changing the Ru:Si ratio will lead to major differences in the resistivity of oxygen-saturated layers after thermal annealing.

Research was conducted to examine the structural changes in plasma-deposited fluorinated silicon dioxide films caused by fluorine incorporation using ring-statistics based mechanism. Fourier transform infrared spectroscopy studies and molecular orbital modeling were employed to explain structural changes in plasma-deposited SiOF films caused by fluorine incorporation. Results demonstrate that an increase in the average Si-O-Si angle within SiOF network with increasing fluorine doping level can be explained based on the corresponding changes in ring statistics of the SiOF network.

Research was conducted to examine the temperature dependence of the properties of heteroepitaxial Y2O3 films grown on Si by ion assisted evaporation. Reflection of high energy electron diffraction, X-ray scattering, Rutherford backscattering spectroscopy channeling, atomic force microscopy and transmission electron microscopy were used to investigate the film properties such as crystallinity, strain and morphology. Results indicate that many defects at the interface region were generated by interface interaction between the Si substrate and the yttrium metal.

A study on the use of granular magnetic thin films as ultra-high density recording media was conducted to investigate magnetic interactions in very thin Fe-SiO2 films. The experiment constructed delta m plots for granular thin films. Measurements of the activation volume for the thinnest films suggest 2D interactions rather than 3D interactions which are associated with very low values of the magnetic viscosity. Experimental methods and results are presented.

Metal alkoxides as the starting precursor materials were used as the metal deposition technique to grow metal oxide films on single crystal oxide substrates and deformation textured metal substrates. The grain alignment, morphology and crystallinity of the oxide films depended on the process conditions and the substrate properties. A range of oxygen partial pressures and temperatures were used in growing epitaxial oxide films on technologically important metal substrates.

Research was conducted to characterized the crystallinity of laser-recrystallized Si films on insulators using micro-Raman imaging. To probe the structure at various depths, a small-angle bevel made by angle lapping of the SOI film was used. The depth profile of the Raman feature reveals that the defect density is high in the region near the interface of Si and SiO2 and that the stress increases toward the top surface of the silicon film.

A study was conducted on the characteristics of electron capture after hot-hole injection into a 131-A silicon dioxide, which was then compared with those after Fowler-Nordheim electron injection. Positive charges were accumulated in the oxide after hole injection from the silicon substrate into the oxide. The low-field electron capture observed may be explained based on the electron tunnelling from the substrate into the positive charge and neutral trap centers created near the substrate-SiO2 interface.

A study was conducted to determine the effectiveness of the separation by implanted oxygen (SIMOX) technique in obtaining the degree of interface quality between the silicon oxide and silicon layers of thin films. The effectiveness of the SIMOX was evaluated using the high-resolution X-ray diffraction (HRXRD) and the HR scanning electron microscopy (HRSEM). Results indicated that the two methods were successful in characterizing the SIMOX samples. The development of the HRXRD spectra simulation procedure was useful in the varied introductions of structural and geometrical parameters.

Ti[O.sub.2] thin films were prepared on electrochemically etched porous Si by anodic oxidative hydrolysis of Ti[Cl.sub.3] for the purpose of solar cell application. We compared electrochemical and photoelectrochemical properties of the Ti[O.sub.2]-deposited porous Si electrodes (Ti[O.sub.2]/porous Si) with those of a porous Si electrode. The Ti[O.sub.2]/porous Si showed prolonged stability of photoluminescence and enhancements of photovoltage and photocurrent by 0.13 V and 67% increase, respectively, in comparison with porous Si due to the reduction of surface traps for charge carriers in the presence of Ti[O.sub.2] thin layer. [Li.sup.+] and [Na.sup.+] ions exhibited intercalation and deintercalation through the electrodeposited Ti[O.sub.2] film.

Charged particle activation analysis was employed to determine the densities of ultrathin silicon oxide gate films less than 5 nm thick and grown at 800-950-degrees C on Si(100) through an ultradry oxidation technique. Analysis of density curve and time-dependent dielectric breakdown lifetime characteristic curve reveal the relationship between density and reliability. Results also suggest that modifications in the films' microscopic structure causes the lifetime enhancement close to the oxidation temperature.

We find that annealing oxides in a [H.sub.2] containing ambient creates positive charge in the dielectric of Si/Si[O.sub.2]/Si structures. The H-induced positive oxide charge is shown to be very different from-radiation-induced oxygen vacancy hole traps (E' centers) in Si[O.sub.2]. We find that three factors strongly influence the ability to create H-induced positive charge: temperature, hydrogen concentration in the ambient, and the density of hydrogen cracking centers. We suggest that over-coordinated O centers are responsible for this charge. The proposed over-coordinated oxygen centers may also account for the equivocal nature of several forms of positive charge that have escaped detection by electron paramagnetic resonance, such as the fixed oxide charge that forms during the thermal oxidation of Si.

The characteristics of oxygen-vacancy defects (E') located at the surface of buried SiO2 layers formed by oxygen ion implantation were investigated using electron spin resonance. The results showed that the exposure of the buried oxide to hydrogen during the chemical vapor deposition process resulted in the enhancement of its sensitivity to defect generation. In addition, a single reoxidation was able to substantially improve the quality of the buried SiO2.

Research was conducted on the physical processes involved in silicon dioxide films on silicon. Trap creation, degradation and band-gap ionization were analyzed. A unified model was consequently developed based on simple kinnetc relationships. Results showed that destructive oxide breakdown is related with effective interface softening.

Electron trapping and thermal detrapping properties in SiO2 prepared by plasma and thermal oxidation were investigated using avalanche electron injection measurement. The results showed that the plasma oxide featured more severe electron trapping. In addition, two electron capture cross sections were observed in the plasma oxide. The electron detrapping process in the plasma oxide was different from that in the thermal oxide.

The plasma characteristics of laser-ablated SiO2 was investigated using optical emission spectroscopy. The results showed that the ablated material consisted of several different ion states of both O and Si. The applicability of local thermodynamic equilibrium dtermined the temperature and electron density determinations. Blowoff in the Si substrates were composed of atomic vapor and particulates. The particulates caused significant damage to the surface of the film.

The characteristics of silicon dioxide films deposited by electron cyclotron resonance plasma enhanced chemical vapor deposition were investigated using Fourier transform spectroscopy and Rutherford backscattering spectroscopy. The results showed that the increased substrate bias resulted in an open structure which was observed to be energetically favored. The structure rsisted chemical attachment during the etching process.

Transmission electron microscopy and x-ray diffraction were used to analyze the structure and crystallization of low- pressure chemical vapor deposited silicon films. The results showed that the transition deposition temperature from amorphous to polycrystalline film was at580 degrees celsius. Diffraction analysis showed that the structural disorder to amorphously deposited films increased as the deposition temperature became higher. Film grain sizes were determined by both the deposition temperature andrate.

A new study investigates the characteristics of low-energy photoluminescence in microcrystalline silicon films.

Electron beam irradiation was used to generate nanometer scale patterns in deposited SiO2. The results showed that SiO2 could be used as a nanometer electron beam resist, and arrays of lines with feature sizes as small as 10 nm were fabricated. O+ ion implantation into the film and subsequent annealing was extremely important to the lithographic properties of the deposited oxide.

The development of a a spatially averaged model of a high density power modulated high density oxygen discharge is presented.

The breakdown of thin and ultrathin silicon dioxide films has been studied by developing a unified model. It is based on the ability of trapped charges to increase the effective local permittivity of silicon dioxide by increasing the polarization. Results indicate that breakdown is associated with the presence of a fixed amount of trapped charges inside the oxide. There is also good agreement between the experimental and theoretical data.

A study was conducted to analyze mechanisms of time-dependent oxide breakdown in thin thermally prepared SiO2 films. The structural transformations of a-SiO2 up to breakdown were simulated using a semiempirical molecular orbital computation technique. Results indicated that the heat of formation and frontier orbital energies of structural transformations explained the physical aspects of the time-dependent dielectric breakdown phenomenon.