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On a analysé, par diffraction de rayons X, des couches minces de carbonitrures de tungstène et de titane obtenues par ablation laser réactive sur des cibles de tungstène et de titane dans une atmosphère de méthane (propane) à faible teneur en azote, sous basse pression. On a montré que les dépôts sont essentiellement constitués de carbures de tungstène et de nitrures de titane. On a obtenu des duretés d'environ 2600 GPa pour les couches à base de tungstène et de 2200 GPa pour les couches à base de titane.

The multipulse excimer laser-reactive ablation of a titanium target in nitrogen has been found to result in a total pressure of the ambient gas in the range 7–70 μbar, in the deposition on to a silicon collector surface of high-purity f c c TiN thin films. These films were hard and adherent to substrate. The deposition rate was 0.03–0.05 nm per pulse for an incident laser fluence of ≥5 J cm−2. For a lower gas pressure of a few microbars the deposits were amorphized with an excess of titanium. For a nitrogen pressure larger than 100 μbar, the layers were contaminated with oxides. The oxides became more abundant with further increase in the gas pressure, and the deposited layer consisted of oxides only when the pressure reached several millibars.

Amorphous hydrogenated silicon (a-Si:H) thin films deposited on a (100) Si wafer by plasma enhanced chemical vapor deposition (PECVD) were irradiated by KrF (λ=248 nm) excimer laser or treated in a plasma jet generated by a capacity coupled RF discharge in N2, respectively. Various techniques such as X-ray photoelectron spectroscopy (XPS), ellipsometry, optical microscopy and microhardness measurements were used to characterize the laser and nitrogen plasma jet induced composition and crystallinity modifications. Oxidation/reduction effects together with crystallization were evidenced in the case of the laser treatment. The formation of different compounds containing Si, C, N and O was observed as an effect of nitrogen plasma treatment.

Amorphous hydrogenated silicon carbide (a-SiC:H) thin films were crystallized by laser treatment. The samples, with a carbon content in the range 0%-50%, were deposited onto Si (100) wafers by plasma enhanced chemical vapor deposition. Various techniques, such as X-ray photoelectron spectroscopy (XPS), infrared (IR) transmission spectroscopy, optical microscopy, and microhardness measurements were used to characterize the laser-induced composition evolution and crystallization processes. The characteristics of the crystallized samples are promising for application as protective coatings for devices used in severe operating conditions.

We studied Ti in-diffusion as an effect of multipulse laser irradiation, in either visible of ultraviolet (u.v.) spectral ranges, of LiNbO3 single-crystalline structures with Ti coatings of two different thicknesses. It is shown that while u.v. (excimer, λ ≈ 308 nm) laser irradiation causes a complete expulsion of the Ti deposit, the visible (ruby, λ ≈ 694·3 nm) laser irradiation at intermediate incident laser fluence (up to ≈ 0·7 J cm-2) promotes efficient Ti in-diffusion from the thin (400 Å width) Ti deposit down to a micrometre range implantation depth.

Amorphous hydrogenated silicon carbide (a-SiC:H) thin films were treated in a capacity coupled r.f. discharge plasma jet working in nitrogen. The samples, with a carbon content in the range of 30%–50%, were deposited onto Si(100) wafers by plasma enhanced chemical vapor deposition. The capacity coupled r.f. discharge (less than 100W) is generated in flowing nitrogen or ammonia in a small distance (1–2 mm) gap, at medium pressure (3–25 torr). The gap is limited by a planar (40 mm diameter) electrode and a nozzle (1–2 mm) opening. Plasma expands as a bright nitrogen plasma jet in a larger vacuumed vessel. The sample's holder (which can be heated) was placed downstream the nozzle at several centimeters distance, being exposed to the plasma beam. In this way the samples (a-SiC:H) were irradiated. Various techniques, such as X-ray diffraction, X-ray photoelectron spectroscopy, Fourier infrared transmission spectroscopy measurements, spectroscopic ellipsometry and microhardness measurements were used to characterize the induced composition evolution towards Si-C-N (SiC-SiN-CN) mixtures.

The fabrication and characterisation of a novel vertical cavity laser for long wavelength operation, which uses two micromachined InP/air-gap mirrors, is reported. The air gaps are realised by selective removal of GaInAs sacrificial layers. Single-mode lasing at room temperature was observed by optical pumping with output powers above 80 µW.