ArF exciraer laser CVD was performed to give epitaxial SiC films on the sapphire or (α-A12O3 (0001) substrate. The rate of film growth was limited by the diffusion of the supplied gases. Small amounts of the gas supply failed to produce the SiC deposition and etched the substrate. The UV light irradiation of the substrate was necessary for the photo-excitation to grow the adherent epitaxial films. Filtered UV light from a D2 lamp revealed that the light with the wavelength shorter than about 310nm was effective for the epitaxial growth. It was found to be essential to excite intermediate products or by-products in the absorbed layer on the substrate. The epitaxial SiC films on the αA12O3 gave blue photoluminescence which may be ascribed to the superstructure of 3C-type SiC crystals.

Spectroscopie ellipsometry is a non-destructive tool for physical characterization without prior preparation of materials.Real time, in-situ measurements can be applied to analyze surface problems, to optimize thin film processing and even to monitor epitaxial growth or thin film deposition. Spectroscopie Eilipsometers built by SOPRA are described. A new instrument using Optical Multi-channel Analysis,(OMA), with a spectral range from 1.1 ev up to 4.8 ev which gives up to 11 ellipsometry spectra per second has been developed. Applications using Spectroscopie Ellipsometry are also discussed .

Laser-induced surface reduction and ablation of piezoelectric oxides is described for the examples of BaTi03 and LiNb03.

The microscopic mechanisms involved in the laser-induced etching of single-crystal (100) Si in Cl2 atmosphere are investigated for the regime of low laser powers.

Thin GaAs-oxide layers have been formed on GaAs (100) surfaces using deep UV light to enhance the oxidation reactions. Two different oxidation reactions were compared by using UV light of wavelengths below and above the O2 dissociation limit, viz, 248 nm and 193 nm respectively. For the light above the O2 dissociation limit which causes ozone formation, oxides formed by direct surface illumination were compared to oxides formed by illumination parallel to the GaAs surface. Metal contacts were deposited in situ to study the effect of the various thin oxides on the Schottky barrier height of contacts to GaAs.

Carrier-driven photochemcial dry etching of semiconductors can be selectively suppressed by ion-implantation-induced defects. The magnitude of this suppression depends on the semiconductor impurity doping concentration, the ion fluence, and the photo-excitation wavelength.

We have demonstrated a method f or the selective-area, laser-assisted liquid-phase etching of 6-μm thick copper conductors, by focusing the 488-μm line of an argon ion laser onto the surface of samples immersed in a dilute solution containing sulfuric acid and hydrogen peroxide. Average etch rates of up to 5.0 μm/s have been achieved, in the process of completely severing 14-μm wide copper lines, with little attendant damage to the underlying layer of polyimide. Two etchant formulations were identified which exhibited large etch rates at elevated temperatures and low enough background etch rates (approximately 1 μm/hr at 0 °C) to be useful in practical applications.

The phenomena occurring when laser radiation interacts with a material submerged in a liquid depend on the power, wavelength, pulse duration, and liquid dielectric properties. Present studies, involving two distinctly different physical situations, show how some interaction modes can be used for surface modification. In the first, a continuouswave CO2 laser-beam progressively pyrolyzes a liquid precursor to form a surface coating. Hexamethylcyclotrisilazane, for example, dissociates to produce highly adherent Si3N4 layers containing 200nm spherical particles. In the second physical situation, intense excimer laser radiation produces dielectric breakdown of the liquid, thus creating a high-temperature plasma and a high-pressure shock wave. Under these conditions, precursor decomposition products alloy the substrate to a depth of lum. Experiments above and below the substrate melt threshold have been used to determine the effects of processing in different power density regimes. A variety of analytical techniques have been employed to determine the compositions of the as-synthesised layers and mechanisms related to the observed phenomena are discussed.

We report the first results of experiments using a focused argon ion laser to locally induce chemical etching of steel and stainless steel in neutral salt solutions for maskless patterning. The solutions include sodium chloride, sodium nitrate and potassium sulfate. Vertical etch rates up to 4 microns/s are observed.

The H and Li profiles in proton-exchanged (PE) LiNbO3, have been measured using elastic recoil detection (ERD). Profiles were determined as a function of crystal orientation, time after PE, annealing temperature, MgO-doping, and added Li-benzoate to the benzoic acid proton source. The proton-exchange process produces Hx Li1−x NbO3 structures where x stabilizes near values of x=0.5 or x=0.7-0.75 depending on specific conditions. The ERD measurements represent the first direct and simultaneous measurements of H- and Li-concentrations in PE LiNbO3 and their variation with process parameters.

Resonance Raman spectroscopy was used to monitor the adsorption of halogen molecules (bromine and iodine) on metal substrates. The Raman bands of chemisorbed, physisorbed and crystalline species were found in the spectra. In the case of bromine, when the temperature was raised from 77 K, the band associated with the chemisorbed species increased in intensity with the concomitant decrease in intensity of the band of crystalline species. A similar increase in the band intensity of the chemisorbed species at the sacrifice of that of the crystalline species was found on continued laser irradiation. The saturation of the band intensity of chemisorbed species was found in the latter case, however. The continued evaporation of bromine vapor onto the substrate surface at 77 K with the simultaneous monitoring of the layer thickness revealed that the initial deposit of bromine onto the substrate did not lead to the chemisorbed species. The accumulation of the crystalline species occurred in its stead. The occurrence of the molecular transfer process from the crystalline species into the chemisorbed species was suggested. The Raman excitation profile showed that bromine molecules adsorbed on a substrate do not dissociate in the wavelength range studied (16000-22000 cm-1). The excitation profile is to be given by Albrecht's A term and roughly corresponds to the absorption spectrum of thin film of bromine on the substrate, which is very difficult to obtain directly.

Experiments were performed to investigate the pulsed excimer laser etching of a chlorinated copper substrate. Time-of-flight mass spectrometric techniques were employed to characterize the mass and velocity distributions of both neutral and ionic species that desorb at laser fluences less than that required to melt bulk Cu or CuCl substrates. The presence of positively charged ions in this work is examined in terms of both photon and electron mediated desorption mechanisms.

Damage-profile tailoring using multi-energy ion implants can produce smooth side walls and deeper etched features with ion-bombardment-enhanced wet etching of LiNb03 than is possible with a single-energy implant. High ion fluences can produce buried microcracks which may contribute to propagation losses commonly observed in ion-implanted waveguides.

Characteristics of ion beam assisted etching (IBAE) for SiO2 have been investigated to reveal'a possibility for maskless etching using focused ion beams. The ion beam assisted etching was done by bombarding 50 keV unfocused ion beams in XeF2 atmosphere and effect of various etching parameter on etching characteristics have been investigated. These are the effects of XeF2 gas pressure, bombarding ion species, bombarding angle and H2 addition, etc. Significant enhancements up to 100 times larger than physical sputtering were achieved. The selectivity of SiO2 to Si could be tailored to specific requirements from 0.1 to 6 by changing the gas mixing ratio. The etching rate was approximately proportional to the energy deposition rate bombarded by ion beam on surface. Carbon contamination on surface after etching were improved by the introduction of XeF2 gas.

A secondary ion mass spectrometry (SIMS) system has been incorporated into the AT&T-BL second generation focused ion beam (FIB) micromachining system. The primary applications are end-point detection and topographical element mapping. End-point detection of Cr micromachining on photomasks was done with raster sizes ranging from 10 μm x 10 μm to 3 μm x 3 μm. SIMS end-points, total ions images, and transmitted light measurements show that the ion-milling can be controlled to stop prior to or after the Cr/glass interface. Mass selected secondary ion images have been obtained for high yield ions such as52Cr+ and27 A1+ on raster fields of 25 μm in time intervals ranging from 20 to 100 sec. Al+ SIMS images of 1 μm lines and spaces from a VLSI test pattern have been obtained.

Mo-Si films on silicon substrates has been prepared by the CO2 laser-initiated aluminothermic reaction. The features of these films have been characterized by RBS, AES, etc. The formation mechanism is discussed.

We have calculated the degree of dopant diffusion which occurs during non-equilibrium incorporation of boron from the silicon surface into the molten silicon induced by a pulsed excimer laser. When a high-power lascr causes the melt front to proceed into the substrate faster than 8 m/s, p+ -doped regions are formed near the surface of the molten silicon because boron atoms cannot diffuse sufficiently fast for the junction depth to reach the maximum melt depth.

In this paper, we present the results of a study to fabricate shallow p+ n junction using Ga FIB implantation in conjunction with rapid thermal annealing (RTA). A focused 75 KeV ion beam with BO mA/cm2 current density and 0.5 μm beam diameter was used to implant Ga into (100) Si substrates at the doses from 1E13 to 5E15/cm2. The annealing temperature is from 600 °C to 1000 °C for various times, 10–30 sec. Secondary ion mass spectrometry (SIMS) and spreading resistance profiling (SRP) were used to measure the implanted Ga atomic and carrier concentration depth profiles. As compared to the conventional broad beam (BB) implantation, the FIB implanted impurity concentration depth profile has a longer tail and thus a deeper p+n junction. The damage generated by the high dose rate implantation is possibly responsible for this phenomenon. The results of SRP measurements of the FIB as-implanted samples show no Scif-anneal ing occured during implantations. p+n diodes fabricated using FIB exhibit good junction properties: ideality factor of 1.1, reverse–bias leakage current of below 5 nA/cm2 at -IV, and breakdown voltage of about 35 V.