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We present a study of the temperature non-homogeneities induced by millisecond laser annealing in advanced CMOS technologies at die level. Because of the design, the device layout at the wafer surface introduces during this anneal significant spatial variations of optical absorption and heat transfer that can induce temperature non-uniformities over the die, often called 'pattern effects'. These temperature variations are becoming a major issue, since they are the origin of significant device properties dispersion. A complete optical and thermal simulation set has been developed to estimate the temperature variations induced by the topologies at the wafer surface during the laser anneal process. The modelling has been validated by either a comparison with another software or reflectometry and electrical measurements on real structures. This work demonstrates that the temperature variations are caused either by optical coupling or by thermal properties dispersion present at the wafer surface at the anneal step. Finally, we demonstrate that the impact of the thin-film interferences and diffraction phenomena is the critical issue for these pattern effects. [ABSTRACT FROM AUTHOR]

Amorphous carbon nitride (a-CN[sub x] ) films were grown on silicon substrates by ArF excimer laser ablation of a graphite target in the presence of nitrogen at various gas pressures. By working at elevated pressures (up to 100 Pa), large amounts of nitrogen can be incorporated into the films (up to 40 at. %, which leads to a strong enhancement of their field emission properties. This behaviour was demonstrated to be mainly related to changes in the surface morphology of the samples, in connection with the development of graphite-like structures. [ABSTRACT FROM AUTHOR]

Abstract. Diamond-like carbon (DLC) films have been grown on Si substrates at ambient temperature by the pulsed-laser ablation technique, using pulses of different durations both in the nano- and picosecond ranges and at various energy fluences. The stability of these films was investigated as a function of thermal anneals performed in UHV conditions up to 1273 K. Their physico-chemical properties have been characterized by different techniques including X-ray photoemission, Auger electron and electron-energy-loss spectroscopies, Raman scattering, spectroscopic ellipsometry and atomic-force microscopy. The thermal stability of the films has been demonstrated to be related to their initial structural (sp[sup 3]/sp[sup 2] ratio) and chemical (contaminant) properties. DLC layers prepared under optimized conditions have been found to show a very good thermal stability up to 900 K. [ABSTRACT FROM AUTHOR]

Abstract. An ArF excimer laser (22 ns, 193 nm) and a hybrid dye/excimer laser system (500 fs, 248 nm) are used to deposit amorphous carbon nitride films at room temperature by ablation of a graphite target in nitrogen atmosphere. The chemical composition and structure of the films is characterized by X-ray photoelectron spectroscopy. In the nanosecond case, the nitrogen content increases with reactive gas pressure up to 45 atomic %, while in the subpicosecond case it remains below 7 at. %. When processed with nanosecond pulses, the films' nitrogen content steeply increases with fluence up to a maximum. The target-to-substrate distance has only minor influence on the amount of nitrogen incorporated into the films. The dependence of the carbon-carbon and carbon-nitrogen bond configurations on the processing parameters is also given. [ABSTRACT FROM AUTHOR]

Abstract. In this work, the excimer-laser-induced crystallization of a-Si films on SiO[sub 2] was investigated using a long-pulse-duration (200 ns) XeCl source. The microstructural analysis of the laser-irradiated area, for incident energy densities comprised between the thresholds corresponding to the surface and full melting, respectively, of the Si layer, was performed by scanning electron microscopy and Raman spectroscopy. A super-lateral-growth regime was evidenced quite comparable to that which occurs when classical excimer laser pulses of short duration (is approximately equal to 20 ns) are used. A numerical simulation of the surface melt dynamics was also performed and compared to the experimental observations. [ABSTRACT FROM AUTHOR]

The solubility of several dopants (Sb, Ga, Bi, In) in laser treated silicon has been investigated. The dopants were introduced by vacuum deposition followed by ruby laser irradiation. Their solubility was determined by Rutherford backscattering spectroscopy measurements in channelling and random conditions. In all cases, a maximum solubility C , much higher than the equilibrium solubility limit C and independent of the pulsed laser energy density, was found. The values obtained are in good agreement with those calculated from a simple model based on phase diagram considerations, using the relationship: where k and k are the equilibrium and effective distribution coefficients. Finally, the existence of a new solubility limit for a laser treatment is discussed. [ABSTRACT FROM AUTHOR]

The concentration of electrically active phosphorus which can be introduced into silicon by conventional high temperature diffusion is limited to about 4 × 10 cm, Phosphorus in excess of this concentration is inactive because it is precipitated and/or paired with doubly charged vacancies according to the Fair-Tsai model. It has been shown recently that this phosphorus can be partly or totally reactivated by irradiation with high energy (1 J/cm) ruby laser pulses of short duration and that more heavily doped junctions can be realized by such treatment. In this work, a systematic study of this effect has been performed using SIMS, RBS, Hall and sheet resistance measurements. The influence of the diffusion and irradiation conditions and also of post irradiation thermal treatment has been considered. The results show that the increase of electrically active phosphorus after laser treatment is not only related to the dissolution of precipitates but also to the dissociation of P V pairs. [ABSTRACT FROM AUTHOR]

Abstract. Silicon-based thin films have been obtained by the direct photodissociation of mono- or disilane gases in a windowless CVD reactor using the vacuum ultraviolet (VUV) argon emission generated by electrical discharges. Atomic force microscopy, Raman scattering and elastic recoil detection analysis techniques were applied to characterize the surface morphology, the structural properties, and the hydrogen content of the deposits, respectively, as a function of the silicon hydride concentration in the feed gas and, to a lesser extent, of the substrate temperature. Independent of the hydride concentration, it is found that the layers have a low hydrogen content of the order of 5% to 10%. On the other hand, their surface roughness is limited to a few nanometers providing that the partial hydride gas pressure in the reactor does not exceed 10 Pa. Raman investigations show that two different types of material can be obtained: either a purely amorphous one for hydride concentrations not exceeding 10% or a mixture of Si submicrocrystals embedded in an amorphous medium for the higher concentrations. Given the conditions of the growth technique used and the photodissociation mechanisms involved, it is concluded that a homogeneous nucleation process occurs already within the gas phase, leading to the formation of nanosized Si grains, that may agglomerate before reaching the substrate where a further growing step eventually takes place. [ABSTRACT FROM AUTHOR]

Two ways of performing the Thermally Stimulated Current (TSC) experiment have been used to investigate vapour grown HgI:i) under light excitation, four peaks are observed at 104, 158, 210, 240 K; ii) under bias excitation, two types of spectra have been obtained with peaks around 160, 240K (type I) and 182, 280 K (type II), respectively. The activation energies have been estimated to be 0.38 eV for the peak showing up at 182 K, and 1.05 eV for the one at 280 K. [ABSTRACT FROM AUTHOR]

In this work, the photoablation of PolyPhenyl-Quinoxaline (PPQ) films is investigated by using the vacuum ultraviolet (VUV) incoherent emission (λ<160nm) from a novel windowless hydrogen (or helium) discharge lamp. A tentative explanation of the film etching process is given through the photochemical reactions which take place in the polymer under VUV illumination. [ABSTRACT FROM AUTHOR]