The ability to study the surface texture of a sol-gel film of lead titanateas it is heated in-situ in an environmental scanningelectron microscope is demonstrated. Measurements of the shrinkage of thefilm at cracks and around delaminations of several microns have been Made.Grain sizes of the final crystalline microstructure were determined to be ∼0.2 μm. The formation of bumps in the film 1–5 μm in size was observed. Thepresence of these features may correlate with the onset ofcrystallization.

Anorthite-glass films have been grown by pulsed-laser deposition onsingle-crystal α-Al2O3 substrates which werepre-thinned to electron transparency. The glass films were crystallized inthe transmission electron Microscope (TEM), which allowed direct observationand video-recording of the crystallization process. Crystallization of thesefilms in the TEM resulted in the formation of hexagonal and orthorhombicanorthite. The orthorhombic phase was the predominant product of glass filmsgrown at elevated substrate temperatures and displayed strong epitaxy withthe underlying substrate. In contrast, the hexagonal phase was the majorconstituent of films grown at ambient substrate temperature and displayed noclear epitaxy with the substrate. The differences in degree of epitaxy andphase structure may be evidence of ordering at the original glass/oxideinterface.

X-ray diffraction analysis was used to study the pyrolytic conversion of apreceramic polysilazane into Si3N4. Quantitative datafor crystallite size, phase composition, and degree of crystallinity versuspyrolysis temperature and atmosphere (N2 and NH3) arepresented. Pyrolytic products produced under N2 and NH3 atmospheres consist of microcrystals of silicon and a- and β-Si3N4. Under both atmospheres, a majority of thechar is crystalline at ∼ 1270°C, and the entire char is crystallized at1400°C. Pyrolysis under an NH3 atmosphere produces nearstoichiometric Si3N4, while pyrolysis under N2 produces a silicon-rich material.

We report in situ high resolution transmission electronmicroscopy studies of NiSi2-Medi-ated crystallization ofAmorphous Si. Compared to conventional solid phase epitaxy of (111) Si, anenhancement of the growth rate by three orders of magnitude was observed andhigh quality twin-free needles of <111> Si were formed.Crystallization occurred via a ledge growth mechanism at the epitaxial TypeA NiSi2/crystalline Si (111) interface. A Model for NiSi2-Mediated crystallization of Amorphous Si involving thepassage of kinks along <110> ledges at theNiSi2/crystalline Si (111) interface is proposed.

Silicon crystallization has been observed to occur in copper/a-Si:H thinfilm bilayers annealed at 280 °C. Copper-silicide formation was observedafter annealing at 200 °C. Samples characterization was made by acombination of several analytical techniques: scanning electron Microscopy,Raman spectroscopy through a microscope probe, Auger electron spectroscopy,elastic recoil detection analysis and Rutherford backscatteringspectrometry. The possible role of hydrogen in this process isdiscussed.

PZT (PbxZr0.4Ti0.6O3) thin filmswere prepared by reactive co-sputtering and annealed by RTA (Rapid ThermalAnnealing). Transformation kinetics and effect of Pb content on thetransformation were intensively studied using EMA (Effective MediumApproximation). It has been found that depending on Pb content as well asRTA temperature, the crystal structure of PZT films changed greatly. Itturned out that the transformation temperature for the perovskite phase canbe lowered and the width of transition temperature region was reduced byincreasing Pb content in the films. Dependence of transformation path on thePb content has been studied.

The crystallization process and microstructural evolution of PZT (52/48)thin films deposited on Pt thin film electrode on Si (100) by reactivemultitarget cosputtering technique have been studied as a function ofpost-annealing temperature and holding time. As annealing temperatureincreases, the Amorphous PZT films as-deposited at low substrate temperatureof 200 °C crystallize into pyrochlore at 450 °C and ferroelectric perovskitephase with pseudo-cubic structure at 550 °C in sequence. X-ray diffractiondata show crystallization into perovskite phase to be complete in 30 Minutesat 550 °C. Furthermore, the change of PZT/Pt/Ti/SiO2/Siinterfacial TEM Morphology during heat-treatment has been closelyscrutinized.

Thin LiTaO3 films were prepared by spin coating of polymerizedsol-gel precursor solution. Films have been deposited on single crystalsilicon substrate, Ti/Pt or SiO2 coated silicon substrate. Filmswere characterized by x-ray diffraction, dielectric and pyroelectricMeasurements. High Curie temperature (above 550 °C) was assumed for LiTaO3 thin films from the temperature dependence ofdielectric constant. Replacing 35% of tantalum by titanium atoms in the LiTaO3 precursor solution has resulted the thin films withCurie temperature of 330 °C. The lower Curie temperature leads to the largerpyroelectric coefficient at room-temperature, which is more than double thatof the undoped LiTaO3 thin films. The dielectric, pyroelectric,and ferroelectric properties have been compared to the single crystal LiTaO3 and ceramic Li0.91Ta0.73Ti0.36O3. LiTaO3 thin films are available by sol-gel process at lowtemperature, and their properties may possibly be controlled by varying thecomposition of the sol-gel precursor solution.

Amorphous precursors are obtained as a result of the precipitation frommagnesium acetate solutions with ammonia in the presence of citric acid.Compared with crystalline precursors they have a higher reactivity and achanged behaviour in calcination process as well as during sintering.Already at 1300 °C sintered pellets are achieved, whereas in technologicalprocess 1700 °C are needed.

Amorphous GeSi films with different thicknesses and oxygen contents wereelectron beam evaporated onto Si (KK)) wafers and wet oxidized at 900 °C for30 Min. If there was no oxygen in the as-deposited film, an epitaxial GeSifilm would be grown after wet oxidation. For the samples with oxygen,epitaxial growth broke down when the thickness of the epitaxy exceeded about200 A and polycrystalline GeSi films were formed. A dedicated STEM (scanningtransmission electron Microscope) was used to characterize the sample afteroxidation. STEM BF (bright field), ADF (annular dark field), and energyfiltered images revealed the presence of small oxide particles in thepolycrystalline GeSi films. X-ray microprobe analysis with a windowlessdetector was employed to identify the oxide particles. The failure of theepitaxy is explained by the random nucleation and growth of GeSi grains onthe oxide particles.

Ceramic PVD coatings have got very often an X-ray Amorphous structure. Thisis regarded for all classes of ceramics like covalent and ionic Materials.These Amorphous materials start to crystallize at temperatures about 800 °C,a quite low temperature for the practical use of such Materials. Thisprevents the propagation of this materials in applications like hightemperature wear protection, oxidation resistivity etc.

This paper describes several possible techniques to increase the thermalstability of the Amorphous state of ceramic PVD-coatings like A1203 and SiCup to 1200 °C. The best way is the incoporation of an additional elementlike nitrogen into the thin filmsl. The change of the mechanical propertiesof alumina leads to new applications like diffusion barriers.

Numerical simulation of zone-Melting recrystallization (ZMR) was conductedto determine the heat transfer dynamics over a wide range of temperatures.ZMR is a thermal processing technique used to recrystallize Materials.Therefore, the thermal effects induced by the ZMR process critically affectthe crystallization dynamics. Parametric studies indicated that theconductive heat flux from the heat source through the gas accounted for atleast 15% of the total energy heating the film for materials with meltingpoints less than 800°C. The influence of this conductive heating has beenneglected in past analyses. Also, Materials with higher melting points areless sensitive to changes in the heat flux from the heat source. Slightvariations of thermal gradients in the film can lead to different qualitiesof crystal, so care must be taken when processing materials with lowermelting points, since they are more sensitive to temperature variation. Thispaper analyzes the dominant modes of heat transfer in ZMR over a wide rangeof temperatures that influence the recrystallization dynamics.

Thin, calcium magnesium silicate glass films have been deposited onto (001)-oriented single-crystal MgO substrates by pulsed-laser deposition (PLD).The substrates were thinned to electron transparency and characterized inthe transmission electron Microscope (TEM) before and after the depositionand following different heat treatments. Energy Dispersive X-raySpectroscopy (EDS) was used in the TEM to characterize the chemistry of thefilms. The heat treatments were performed both in situ and ex situ. Directevidence for crystallization was obtained by in-situ experiments at 950°C.Subsequent heat treatments were performed for longer times in air between950°C and 1100°C. The crystallized phase was found to be Monticellite (CaMgSiO4) and the crystallites show moderate epitaxy with theunderlying substrate. Films contaminated with aluminum resulted in thegrowth of magnesium aluminate spinel (MgAl2O4)epitaxially from the substrate. These observations of epitaxy indicated thatcrystallization initiated at the surface of MgO.

There are no reported gold-rich alloys that are both readily glass forming(RGF) upon rapid solidification processing (RSP) and, in the glassy state,have crystallization temperatures Tc sufficiently high to insurelong metastable life times at room temperature. A representative of a newfamily of ternary gold-based glasses is described that contain Cu and a rareearth (RE) Metal (or Y), with total addition element concentrations as lowas 15 at. pet., and its crystallization characteristics are reported. UnderRSP processing by arc furnace hammer-and-anvil quenching, the alloy Au0.80Cu0.10Y0.10 readily forms aductile glass, with Tc = 685 K, ΔHc = 1.25 kJ/g-Moleand an activation energy of crystallization ΔE3 (cryst.) = 190kJ/g-Mole.

In this work we describe a flash evaporation system specially built toproduce Amorphous films of III-V compounds and characterize GaSb films usingoptical, electrical and X-Ray diffraction Measurements. Changes in thecomposition of the GaSb samples were obtained by the use of differentcrucible temperatures. In such samples, consequently, the optical absorptionedge and the DC electrical conductivity were Modified. The departure fromstoichiometry in GaSb films is analyzed on the basis of these results whichcan be used as an evidence of the chemical disorder. This kind of disorderis represented by either wrong bonds or sites with differentcoordination.

Thermal annealing with a sequence of increasing temperatures first induceddetectable variations in the optical absorption edge and in the vibrationalproperties of the Amorphous GaSb. These variations are compatible with theGaSb local ordering and were observed by Raman scattering and infraredabsorption spectra. The annealing at higher temperatures allowed thecrystallization of the material confirmed by X-Ray diffraction. From theseexperimental results a crystallization mechanism based on the segregation ofSb excess coming from the crystallized regions toward the Amorphous tissueis proposed.

The effects of addition of glass fiber and HMS4 carbon fiber on thecrystallization of nylon 6,6 has been investigated using DSC and polarizedoptical Microscopy (POM). DSC observations indicate that HMS4 fiber lowersthe supercooling required to initiate crystallization. A transcrystallinelayer is also observed in the near-fiber region of carbon fiber-reinforcedcomposites after DSC. The presence of transcrystallinity and the earlieronset of crystallization for this composite are due to heterogeneousnucleation on carbon fiber surfaces. DSC Measurements of nylon 6,6 withglass fibers show supercoolings similar to those of neat nylon 6,6.Transcrystallinity is also absent in the glass-reinforced composites. Theseglass fibers appear to be weak nucleation catalysts. Differenttranscrystalline layer thickness is found to be influenced by thermalprocessing condition. In addition to transcrystallinity, the HMS4 carbonfiber also influences the bulk morphology of the nylon 6,6.

We have succeeded in obtaining nondoped, thin poly-Si film (thickness ∼500Å)with excellent crystallinity and large grain size (Maximum grain size ∼4.5 μm) by an excimer laser annealing Method, which offers the features oflow-temperature processing and a short processing time. The grain sizedistribution shrinks in the region around 1.5 μ m and this poly-Si filmexhibits a strong (111) crystallographic orientation. Poly-Si thin filmtransistors using these films show quite a high field effect mobility of 440cm2/V · s below 600°C process.

We have experimentally Investigated the effects that are associated withMultiple-pulse irradiation in the excimer laser processing of thin Si filmson SiO2. Double-pulse irradiation experiments revealed results,which are consistent with that which is known from single-pulsecrystallization experiments, and these experiments confirm the applicabilityof the transformation scenarios, which were derived from singlepulse-induced crystallization experiments [1,2]. The results from theMultiple-pulse irradiation experiments clearly show that gradual andsubstantial grain enlargement can occur — and only occurs —when the irradiation energy density is close to but less than the level thatis required to melt the film completely. Based on these findings, we arguethat the grain enlargement effect is a near-complete melting phenomenon that is associated with polycrystalline Si films, andwe present a grain boundary melting model to account for this phenomenon. Abrief discussion on the apparent similarities and physical differencesbetween the observed phenomenon and the solid state grain growth processesis provided herein.

For fast-pulse laser-crystallized thin-film Si on non-crystallinesubstrates, the average grain size exhibits a peak as a function excimerlaser energy density at a characteristic laserfluence FM. Theaverage grain size increases with increasing laser fluence and can reach amaximum value on the order of 10 pm or about 100 times the film thickness.The grain size then decreases with further increases in fluence. This peakin grain size is accompanied by a similar peak in the Hall electron mobilityand x-ray scattering intensity. Our experiments have investigatedas-deposited and ion-implanted samples, using a double-scan lasercrystallization process. Devices have also been fabricated and studied. Theresults are consistent with the increase in grain size occurring because ofthe destruction of nucleation sites with increasing laser fluence (i.e.,increased heating and complete Melting). But substrate damage occurs in thevicinity of FM, creating nucleation sites which give rise tosmall grain sizes in the solidified film. The disruption of the interfacecauses substantial current leakage through the dielectric of bottom-gatetransistors, implying that devices should be laser fabricated below Fm.

Excimer laser crystallized silicon films have been studied as a function ofthe number of laser shots, and the influence of the use of suchpolycrystalline films in thin film transistors (TFTs) has also beeninvestigated. It is found that electron Mobility, one of the most importantof all TFT characteristics, increases monotonically with the number ofirradiations, with maximum mobility being obtained at about 20 shots. Thisresult is not due to grain size, since transmission electron microscopyindicates that the number of laser shots does not affect grain size inpolycrystalline silicon films. Raman studies and TFT carrier transportanalysis, on the other hand, suggest that this increase in electron mobilitymay be explained by the decrease in grain boundary defects and defectsinside grains.