Showing papers in "MRS Proceedings in 1982"
TL;DR: In this paper, it was shown that circularly polarized light can induce surface ripples, with the damage structure showing a dependence on the sense of rotation, and time resolved results of the formation of the ripples to illustrate the essential dynamical processes that occur.
Abstract: Laser induced periodic surface structure can be understood as a universal phenomenon which occurs when high intensity pulses are absorbed near the surface of solids or liquids. The phenomenon occurs on metals, semiconductors and insulators because of the interference between the incident pulse and an induced “radiation remnant”. This scattered field may be enhanced by the existence of true surface modes such as surface plasmons or phonon-polaritons but this is not essential. The universality characteristics include beam polarization, since we show that circularly polarized light can induce surface ripples, with the damage structure showing a dependence on the sense of rotation. We also present time resolved results of the formation of the ripples to illustrate the essential dynamical processes that occur.
415 citations
TL;DR: In this article, various techniques are described to obtain information about metastable equilibrium from measured stable equilibrium data, including extra-polations of phase boundaries as functions of temperature, pressure or composition.
Abstract: During rapid solidification, the nucleation and/or growth of a thermodynamically stable phase may be difficult. In this case the liquidus, solidus or other thermodynamic data for a metastable phase are important for the interpretation and prediction of the phases present in rapidly solidified materials. In this paper various techniques are described to obtain information about metastable equilibrium from measured stable equilibrium data. Extra-polations of phase boundaries as functions of temperature, pressure or composition (including a new component) into regions of metastability can often be constructed directly on the equilibrium diagram. These constructions can be performed more quantitatively with analytical methods using thermodynamic modelling of the free energy functions consistent with measured data. A number of examples are considered including a discussion of metastable liquid miscibility gaps, metastable eutectic and peritectic reactions, pressure diagrams and metastability in ternary alloys to indicate the possible product phase selection. A coupling of metastable phase diagrams with a solidification kinetics analysis can contribute towards effective alloy design and processing during rapid solidification.
56 citations
TL;DR: In this paper, the intrinsic kinetics of solid phase epitaxy (SPE) in ion-implanted and UHV-deposited films are discussed with respect to a proposed depression in the amorphous Si melting temperature.
Abstract: We review recent work on the kinetics of laser-induced solid phase epitaxial crystallization of silicon as determined from time-resolved reflectivity measurements. Specific topics which are addressed include: the intrinsic kinetics of solid phase epitaxy (SPE) in ion-implanted and UHV-deposited films; SPE rate enhancement by implanted dopant atoms and the effects of electrical compensation on the SPE rate; and the temperature dependence of SPE and competing processes in samples containing impurity atoms at concentrations exceeding the solid solubility limit. The high temperature kinetics results are compared with predictions from transition state theory and are discussed with respect to a proposed depression in the amorphous Si melting temperature.
53 citations
TL;DR: In this paper, an excimer laser is used to photochemically deposit thin films of silicon dioxide, silicon nitride, aluminum oxide, and zinc oxide at low temperatures (100-350deg;C).
Abstract: An excimer laser is used to photochemically deposit thin films of silicon dioxide, silicon nitride, aluminum oxide, and zinc oxide at low temperatures (100–350deg;C). Deposition rates in excess of 3000 A/min and conformal coverage over vertical walled steps were demonstrated. The films exhibit low defect density and high breakdown voltage and have been characterized using IR spectrophotometry, AES, and C-V analysis. Device compatibility has been studied by using photodeposited films as interlayer dielectrics, diffusion masks, and passivation layers in production CMOS devices. Additionally, we have deposited metallic films of Al, Mo, W, and Cr over large (>5 cm 2 ) areas using UV photodissociation of trimethylaluminum and the refractory metal hexacarbonyls. Both shiny metallic films as well as black particulate films were obtained depending on the deposition geometry. The black films are shown to grow in columnar grains. The depositions were made at room temperature over pyrex and quartz plates as well as silicon wafers. We have examined the resistivity, adhesion, stress and step coverage of these films. The films exhibited resistivities at most ∼20 times that of the bulk materials and tensile stress no higher than 7 × 10 9 dynes/cm 2
33 citations
TL;DR: In this paper, the consequences of growing in a hydrogen ambient are discussed in detail and it is shown how complexes of neutral defects produce electrically active centers, and the compromises involved in the selection of zone refining and crystal grower parts and ambients are discussed.
Abstract: The germanium crystals used for the fabrication of nuclear radiation detectors are required to have a purity and crystalline perfection which is unsurpassed by any other solid material. These crystals should not have a net electrically active impurity concentration greater than 10l0 cm−3 and be essentially free of charge trapping defects. Such perfect crystals of germanium can be grown only because of the highly favorable chemical and physical properties of this element. However, ten years of laboratory scale and commercial experience has still not made the production of such crystals routine. The origin and control of many impurities and electrically active defect complexes is now fairly well understood but regular production is often interrupted for long periods due to the difficulty of achieving the required high purity or to charge trapping in detectors made from crystals seemingly grown under the required conditions. The compromises involved in the selection of zone refining and crystal grower parts and ambients is discussed and the difficulty in controlling the purity of key elements in the process is emphasized. The consequences of growing in a hydrogen ambient are discussed in detail and it is shown how complexes of neutral defects produce electrically active centers.
31 citations
TL;DR: In this paper, a potentially mobile species in leachate from a breached radioactive waste repository, was removed from a brine solution by precipitation with sulfide, iron, and ferrous sulfide at environmental pH's.
Abstract: Pertechnetate oxyanion (/sup 99/TcO/sub 4//sup -/), a potentially mobile species in leachate from a breached radioactive waste repository, was removed from a brine solution by precipitation with sulfide, iron, and ferrous sulfide at environmental pH's. Maghemite (..gamma..-Fe/sub 2/O/sub 3/) and goethite (..cap alpha..-FeOOH) were the dominant minerals in the precipitate obtained from the TcO/sub 4//sup -/-ferrous iron reaction. The observation of small particle size and poor crystallinity of the minerals formed in the presence of Tc suggested that the Tc was incorporated into the mineral structure after reduction to a lower valence state. Amorphous ferrous sulfide, an initial phase precipitating in the TcO/sub 4//sup -/-ferrous iron-sulfide reaction, was transformed to goethite and hematite (..cap alpha..-Fe/sub 2/O/sub 3/) on aging. The black precipitate obtained from the TcO/sub 4//sup -/-sulfide reaction was poorly crystallized technetium sulfide (Tc/sub 2/S/sub 7/) which was insoluble in both acid and alkaline solution in the absence of strong oxidants. The results suggested that ferrous- and/or sulfide-bearing groundwaters and minerals in host rocks or backfill barriers could reduce the mobility of Tc through the formation of less-soluble Tc-bearing iron and/or sulfide minerals. 12 references, 2 figures, 2 tables.
29 citations
TL;DR: In this paper, the impurity trapping process using Monte Carlo simulation data from the kinetic Ising model is discussed and the dependence of impurity concentration in the crystal on the solidification rate is calculated.
Abstract: Laser annealing experiments on silicon have shown that rapid solidification can trap large amounts of certain impurities in the crystal lattice. Concentrations that exceed the equilibrium solubility limits by several orders of magnitude have been obtained. In this paper we discuss the impurity trapping process using Monte Carlo simulation data from the kinetic Ising model. The dependence of the impurity concentration in the crystal on the solidification rate is calculated. The simulation data are compared with recent laser annealing results for bismuth and indium. Excellent agreement between the model and the bismuth experiments is obtained. The larger trapping rate on the (111) relative to the (100) orientation is found to be caused by the slower crystallization kinetics on the (111) face. Similar results are obtained for indium, although the difference in trapping on the (111) and (100) faces is somewhat smaller in the model than in the experiment.
27 citations
TL;DR: In this paper, a new type of defects were found to be present in swirl-free and nonstriated distribution regions and to become invisible by doping gallium, which led to the conclusion that they are microprecipitates produced from residual oxygen impurity in FZ crystals.
Abstract: Microdefects in striated (swirl defects) and nonstriated distribution (D-defects) have been observed in float-zoned crystals doped with various impurities by x-ray topography following copper decoration. A new type of defects were found to be present in swirl-free and D-defect-free regions and to become invisible by doping gallium. This gallium effect led to the conclusion that they are microprecipitates produced from residual oxygen impurity in FZ crystals. Effects of various impurities on defect formation indicate that D-defects are of vacancy agglomerates. It was observed that swirl defects are formed when the temperature gradient near the interface is high, and that their formation is suppressed by doping nitrogen. Formation processes of microprecipitates, swirls, and D-defects are discussed on the basis of observation of their mutual interaction and the impurity effects.
24 citations
TL;DR: In this paper, an argon ion laser-based apparatus has been used to deposit metal by pyrolytic decomposition of metal alkyl and carbonyl compounds, in order to evaluate the results of these studies and their implications for the high-speed creation of micron-scale metal structures in ULSI systems.
Abstract: Mechanisms for laser-driven pyrolytic deposition of micron-scale metal structures on crystalline silicon have been studied. Models have been developed to predict temporal and spatial properties of laser-induced pyrolytic deposition processes. An argon ion laser-based apparatus has been used to deposit metal by pyrolytic decomposition of metal alkyl and carbonyl compounds, in order to evaluate the models. These results of these studies are discussed, along with their implications for the high-speed creation of micron-scale metal structures in ULSI systems.
23 citations
TL;DR: In this article, the authors showed that the value of glass surface area to solution volume ratio (SA/V) can strongly influence the leaching rate of PNL 76-68 glass.
Abstract: The value of glass surface area to solution volume ratio (SA/V) can strongly influence the leaching rate of PNL 76-68 glass. The leaching rate is largely governed by silicon solubility constraints. Silicic acid in solution reduced the elemental release of all glass components. No components are leached to depths greater than that of silicon. The presence of the reaction layer had no measurable effect on the rate of leaching. Accelerated leach testing is possible since PNL 76-68 glass leaching is solubility-controlled (except at very low SA/V values). A series of glasses leached with SA/V x time = constant will yield identical elemental release.
23 citations
TL;DR: In this article, a review summarizes the present status of experimental methods and results, including luminescence and capacitance spectroscopy as well as mapping and imaging techniques using electron-microscopes.
Abstract: Simple models have been suggested to predict electronic properties of lattice defects in semiconductor crystals: dislocations ought to act via the acceptor character of dangling bonds, and small-angle grain boundaries ought to consist of regular arrays of dislocations. The actual situation in most semiconductors is, however, much more complicated. The observed electrical effects of dislocations do not confirm the dangling-bond concept, they are affected by dissociation and reconstruction. There appear to be differences between straight and kinked dislocations. Dislocations owe much of their electronic behavior to clouds and precipitates of impurities; oxygen in silicon plays a significant role. This review summarizes the present status of experimental methods and results, including luminescence and capacitance spectroscopy as well as mapping and imaging techniques using electron-microscopes.
TL;DR: In this article, the effect of surface layer formation on the surface of waste glass is considered and a leaching model is developed to describe the leaching behavior of more complicated waste glasses that contain large amounts of iron, manganese, and aluminum.
Abstract: Interdiffusion and matrix dissolution corrosion modes are inadequate to describe fully the leaching behavior of the more complicated waste glasses that contain large amounts of iron, manganese, and aluminum as will many other elements. A further process, surface layer formation, that must be considered when developing a model describe waste glass leaching has been identified. This process consists of the formation of a layer of insoluble material such as the hydroxides of iron, manganese and other insoluble compounds on the surface of waste glass as it corrodes. This paper describes work leading to the development of a leaching model in which the effect of surface layer formation is considered.
TL;DR: In this article, it was shown from experiments that atomic and magnetic ordering reactions exert a mutual influence on each other, and that a strong depression of the Curie temperature is observed with the onset of atomic long range order (lro) as compared to the extrapolation of T c from the random alloys, see Fig. 1.
Abstract: It can be concluded from experiments that atomic (also called “chemical”) and magnetic ordering reactions exert a mutual influence on each other. In bcc Fe-Al alloys a strong depression of the Curie temperature is observed with the onset of atomic long range order (lro) as compared to the extrapolation of T c from the random alloys, see Fig. 1. In fcc Co-Pt alloys a depression of the critical temperature of atomic lro L1 2 →A1 is observed in the Co-rich alloys which are ferromagnetic, as compared to the Pt-rich counterparts which are paramagnetic, see Fig. 2. In this instance it should be noticed that this assymetry is not observed in Ni-Pt allovs where the Curie temperature is inferior to the critical temperatures of atomic lro [1].
TL;DR: In this article, the role of vacancies and self-interstitials in self-and impurity diffusion in silicon above about 700°C is discussed and the existence and the nature of a recombination barrier slowing down the recombination process are discussed in this context.
Abstract: The paper highlights recent progress in understanding the role of vacancies and self-interstitials in self- and impurity diffusion in silicon above about 700°C. How surface oxidation of silicon leads to a perturbation of the pointdefect population is described. An analysis of the resulting oxidationenhanced or -retarded diffusion of group III and group V dopants shows that under thermal equilibrium as well as under oxidation conditions both vacancies and self-interstitials are present. For sufficiently long times vacancies and self-interstitials attain dynamical equilibrium which involves their recombination and spontaneous thermal creation in the bulk of silicon crystals. The existence and the nature of a recombination barrier slowing down the recombination process are discussed in this context. Recent experimental and theoretical results on the diffusion of gold in silicon enable us to determine the selfinterstitial component of silicon self-diffusion and to obtain an estimate of the respective vacancy contribution. The two components turn out to be of the same order of magnitude from 700°C up to the melting point.
TL;DR: In this article, the interface atomic structure in epitaxial cobalt and nickel disilicides on silicon using high-resolution transmission electron microscopy was studied and the results were discussed in the light of silicide nucleation and growth.
Abstract: We have studied interface atomic structure in epitaxial cobalt and nickel disilicides on silicon using high-resolution transmission electron microscopy. By employing UHV techniques during deposition and reaction we have grown truly single-crystalline NiSi2 and CoSi2 films on (111) Si and in the former case on (100) Si. These films are shown to be continuous to below 10A thickness. By close control over preparation conditions, afforded by UHV, we can greatly influence the nucleation and growth of these films to the extent, for example with NiSi2 on (111)Si, of yielding continuous single-crystal films with either of two orientations as desired. Whilst in the (111) NiSi2 on Si system the interfacial structure invariably appears to well-fit a model in which metal atoms nearest to the interface are 7-fold co-ordinated, for (111) CoSi2 on Si agreement is generally better with a model involving 5-fold co-ordination of these atoms. A misfit dislocation core is also imaged. Results are discussed in the light of silicide nucleation and growth. The structure and stability of the (100) NiSi2 on Si interface is also considered.
TL;DR: In this article, a double hydration layer penetrating into the glass and the formation of alteration products on the glass surface was studied as a function of time, temperature, glass composition and water vapor pressure.
Abstract: Aging of simulated nuclear waste glass by contact with a humid atmosphere results in the formation of a double hydration layer penetrating into the glass and in the formation of alteration products on the glass surface. This hydration process has been studied as a function of time, temperature, glass composition and water vapor pressure. A dual stage hydration rate was observed and rate constants were determined at each temperature. An Arrhenius plot for the initial stage alteration rate indicates the reaction mechanism does not change between the temperature limits of the experiment (120 to 240/sup 0/C). This conclusion is supported by the sequence of mineral formation on the surface. This hydration process provides a means of accelerating aging reactions while simulating conditions that may exist in a nuclear waste repository.
TL;DR: In this paper, a CO 2 laser photodissociation of silane was used as the excitation source for hydrogenated amorphous silicon growth by a horizontal configuration, where the laser beam was sent parallel to the substrate surface inside a flux reactor, and its energy was used to excite and dissociate the silane molecules.
Abstract: Some results on hydrogenated amorphous silicon growth by CO 2 laser photodissociation of silane are reported. A 100 W CW CO 2 laser was used as the excitation source. A horizontal configuration was adopted, where the laser beam is sent parallel to the substrate surface inside a flux reactor, and its energy is used to excite and dissociate the silane molecules flowing near the solid surface. The laser has no direct heating effect on the substrate, which is independently heated by an oven. The photoproduced radicals by interacting with the surface grow a film at a rate strongly depending on silane pressure, substrate temperature and laser intensity. This experimental configuration allows depositions on large areas, owing to the large number of reactant molecules involved in the photochemical process. Moreover, material can be produced with a continuously variable hydrogen content, since the substrate temperature required for obtaining depositions can be as low as room temperature and adjusted independently of the other process parameters. The film properties are similar to those of the glow discharge deposited material. The film amorphousness and the hydrogen presence either in monohydride and dihydride groups are evidenced by x-ray patterns and ir spectra. Results on the electrical and optical properties are also reported.
TL;DR: Silicon avalanche photodiodes have been shown to be a potential replacement for vacuum tube photomultipliers in many nuclear scintillation detector applications as discussed by the authors, which makes them ideally suited to scintillator detector applications where overall size and ruggedness are a major concern.
Abstract: Silicon avalanche photodiodes have recently been shown to be a potential replacement for vacuum tube photomultipliers in many nuclear scintillation detector applications. The large active area, low noise, and ease of use of these solid-state photomultipliers makes them ideally suited to scintillation detector applications where overall size and ruggedness are a major concern. Historically, avalanche photodiodes have been limited for use in this capacity by small active areas, low internal gains, and poor optical sensitivity at the wavelengths at which most solid scintillator materials emit. Recent advances as the result of research aimed directly at the solution to these problems however, have successfully demonstrated one inch active area silicon avalanche photodiodes which produce a FWHM resolution of 9.5% for Cs137 at room temperature when coupled to a 1″ × 1″ NaI(Tl) scintillation crystal. Improvements to both material quality and device structure have advanced the state-of-the-art to make silicon avalanche photodiodes a viable alternative in scintillation gamma spectroscopy as well as for large area optical, beta, and low energy x-ray detectors.
TL;DR: In this paper, the concentration and temperature dependence of thermodynamic mixing functions of liquid alloys with compound formation tendency, which often exhibit large deviations from a regular behavior, can be calculated according to an association model using only a few parameters which have a definite physical significance.
Abstract: The concentration and the temperature dependence of thermodynamic mixing functions of liquid alloys with compound formation tendency, which often exhibit large deviations from a regular behavior, can be calculated according to an association model using only a few parameters which have a definite physical significance. The results obtained for binary and ternary alloy melts with one ore more, simultaneously occurring, binary or ternary associates are in good accordance with the experimental values. For the calculation of phase diagrams, the association model enables a correct extrapolation into concentration and temperature regions for which no experimental results are available. The occurrence and the borderline of miscibility gaps in liquid alloys with strong compound forming tendency can be quantitatively described.
TL;DR: In this article, it has been shown that between 10 and 20% of a simulated PW-4b radwaste composition can be incorporated into a single nhase with the MaZr2 P3 o12 structure.
Abstract: It has been shown that between 10 and 20% of a simulated PW–4b radwaste composition can be incorporated into a single nhase with the NZP (= ‘MaZr2 P3 o12’) structure. By changing the P/Na and Zr/Na molar ratios (i.e., adjusting the crystal chemical model of where each ion is located in the structure) it has been possible to outline a very ‘forgiving’ compositional regime both at the 10% and the 20% waste loading level within which one obtains one ([NZP]) or two ([NZP] and [monazite]) phases. We have also succeeded in substituting Tio2 for Zro2 in making a TiO2-rich [NTP] waste form analogous to the [NZ]] materials. Thus we have succeeded in creating monophasic and diphasic ceramic waste forms which can be sintered below 1000° C. Only preliminary leach data have been obtained at 25° and 300°C, and they place this material with good ceramic forms.
TL;DR: In this article, the authors review the current understanding of laser-induced silicon thin film crystal growth on bulk amorphous substrates and propose a model for oriented nucleation and show that the silicon reflectivity jump on melting coupled with radiant heating lead naturally to this autonucleation mechanism.
Abstract: In this paper we review the current understanding of laser-induced silicon thin film crystal growth on bulk amorphous substrates. We propose a model for oriented nucleation and show that the silicon reflectivity jump on melting coupled with radiant heating lead naturally to this autonucleation mechanism. We then survey various techniques for control of lateral epitaxial growth and conclude with the results of some recent electrical device characterization.
TL;DR: In this article, the authors compared the corrosion behavior of the NCS and ABS and discussed the current understanding of ABS glass corrosion in terms of mechanisms, kinetics, surface film formation and thermodynamics.
Abstract: The alkali-borosilicate (ABS) system provides the basis for a wide variety of commercially important products among which are the nuclear waste glasses. Although a large number of investigations have been undertaken in the last five years, the corrosion mechanisms of the ABS glasses have not been characterized nearly as well as for the soda-lime-silicate (NCS) glasses commonly used for containers. It is well known that the corrosion of the latter glasses involves ion exchange, network dissolution, and precipitation mechanisms resulting in the development of one of five types of surface films. In the present paper we compare the corrosion behavior to the ABS and NCS glasses and discuss our current understanding of ABS glass corrosion in terms of mechanisms, kinetics, surface film formation and thermodynamics.
TL;DR: In this paper, the production of photoluminescence lines in terms of carbon and oxygen doping and of the heating temperature and duration was studied and first results as to a level scheme of the P (0.7672 eV) line were reported.
Abstract: Cz silicon samples heated to 450 ° C or higher temperatures for several hours exhibit many sharp photoluminescence lines well below the band edge. We study the production of the lines in terms of carbon and oxygen doping and of the heating temperature and duration. First results as to a level scheme of the P (0.7672 eV) line are reported.
TL;DR: In this paper, thermal donors are viewed as metastable oxygen clusters which lower the compressive strain of the surrounding silicon matrix via bonding of 2p oxygen lone pair orbitals, and it is shown how this bonding can result in shallow double donor states.
Abstract: Our knowledge of phenomena connected to the early stages of oxygen clusters, especially their electrical activity is reviewed. In addition to the well-known 450°C thermal donors, ‘new oxygen donors’, which occur in ca. 650°C annealing, have emerged in conjunction with low temperature processing for VLSI and are discussed. The existing models of thermal donors are reviewed. In a new model of thermal donor formation, thermal donors are viewed as metastable oxygen clusters which lower the compressive strain of the surrounding silicon matrix via bonding of 2p oxygen lone pair orbitals. It is shown how this bonding can result in shallow double donor states.
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TL;DR: In this article, a thermodynamic model based on the regular solution approximation is presented and a formalism, suitable for phases with an arbitrary number of elements and sublattices is described.
Abstract: A thermodynamic model, based on the regular solution approximation is presented and a formalism, suitable for phases with an arbitrary number of elements and sublattices is described. A new concept, the component array, is introduced in order to simplify the analytical expressions for the Gibbs energy. The mathematical complexity of the model has been solved by the implementation of the model as a part of a general software system for thermochemical and phase diagram calculations by computer. The sublattice model is suitable for describing phases where the difference in size, charge or electronegativity causes a deviation from random mixing of the atoms in a manner which can be described as long range order. This is the case for interstitial solutions and many intermetallic phases, but also for ionic liquids and slag systems. The application of the model to several alloy system will be described.
TL;DR: In this article, a model is developed to predict the boundary spacing as a function of scan rate and temperature gradient, and the model is used to predict boundary spacing for flat panel displays.
Abstract: The lure of flat panel displays has stimulated much research on the crystallization of silicon films deposited on large-area transparent substrates In most respects, fused quartz is ideal It has high purity, thermal shock resistance, and a softening point above the silicon melting temperature Unfortunately, fused quartz has such a small thermal expansion that the silicon film cracks as it cools This problem has been attacked by patterning with islands or moats before and after crystallization, by capping, and by using silicate glass substrates that match the thermal expansion of silicon The relative merits of these methods are compared Melting of the silicon film to achieve high mobility has been accomplished by a variety of methods including lasers, electron beams, and strip heaters For low melting temperature glasses, surface heating with a laser or electron beam is essential Larger grains are obtained with the high bias temperature, strip heater techniques The low-angle grain boundaries characteristic of these films may be caused by constitutional undercooling A model is developed to predict the boundary spacing as a function of scan rate and temperature gradient
TL;DR: In this paper, laser-induced fluorescence experiments have been carried out during CF4/O2/H2 plasma etching of Si and SiO2, and the results are correlated with etch rates.
Abstract: Laser-induced fluorescence experiments have been carried out during CF4/O2/H2 plasma etching of Si and SiO2. Measurements of relative CF2 radical concentrations as a function of rf power, frequency, pressure, and gas composition are reported. The results are correlated with etch rates of Si and SiO2. The balance between CF2 and F concentrations is shown to influence the etching process strongly.
TL;DR: Stimulated growth of single crystalline GaAs has been obtained by irradiation of (100) oriented GaAs substrates inside an MOCVD reactor with a pulsed Nd-YAG laser as mentioned in this paper.
Abstract: Stimulated growth of single crystalline GaAs has been obtained by irradiation of (100) oriented GaAs substrates inside an MOCVD reactor with a pulsed Nd-YAG laser. Process temperatures have been varied between 540°C and 360°C. In the non-irradiated areas, below 480°C substrate temperature the growth rate decreases rapidly, whereas in the irradiated part of the substrate epitaxial layers could be grown in the whole temperature range investigated. Below 450°C, the growth is reaction limited.
TL;DR: In this article, single crystallites of W greater than 100 pm tall were deposited using a Kr laser on Si substrates, and the deposition initiation and rate were correlated with irradiation conditions, the laser generated surface temperature and the changing optical properties of the filmμsubstrate during deposition.
Abstract: Metal, dielectric and semiconductor films have been deposited by laser chemical vapor deposition (LCVD) using both pulsed and cw laser sources on a variety of substrates. For LCVD on substrates such as quartz, the deposition was monitored optically in both transmission and reflection using a collinear visible laser and the depositing CO2 laser. Deposition initiation and rate were correlated with irradiation conditions, the laser generated surface temperature, and the changing optical properties of the filmμsubstrate during deposition. Single crystallites of W greater than 100 pm tall were deposited using a Kr laser on Si substrates.
TL;DR: Si 3 N 4 films have been deposited on Si by using 193 nm ArF excimer laser radiation to initiate the reaction of SiH 4 and NH 3 at substrate temperatures between 200-600°C as mentioned in this paper.
Abstract: Si 3 N 4 films have been deposited on Si by using 193 nm ArF excimer laser radiation to initiate the reaction of SiH 4 and NH 3 at substrate temperatures between 200–600°C. Stoichiometric films having physical and optical properties comparable to those produced using low-pressure chemical vapor deposition (LPCVD) have been produced. The dielectric properties of the films are at present inferior to those of LPCVD material.