Recent research on carbon nitride thin films grown using pulsed laser deposition combined with atomic beam techniques is reviewed. the composition, growth mechanism and phases of these films have been systematically investigated. the nitrogen composition was found to increase to a limiting value of 50% as the fluence was decreased for laser ablation at both 532 nm and 248 nm wavelengths. Time of flight mass spectroscopy investigations of the ablation products have shown that the fluence variations affect primarily the yield of the carbon reactant. these experiments demonstrate that the overall film growth rate determines the average nitrogen composition, and furthermore, suggest that a key step in the growth mechanism involves a surface reaction between carbon and nitrogen. INfrared spectroscopy has been used to assess the phases present in the carbon nitride thin films as a function of the overall nitrogen content. these measurements have shown that a cyanogen-like impurity occurs in films with nitrogen compositions greater than 30%. Studies of thermal annealing have shown, however, that this impurity phase can be eliminated to yield a single phase C2N material. IN addition, systematic studies of the electrical resistivity and thermal conductivity of the carbon nitride films are discussed.

Amorphous carbon films (a-C) deposited by the anodic vacuum arc on Si substrates were implanted with nitrogen using the Plasma Immersion Ion Implantation (PIII) technique to form carbon nitride films (CNX). Scanning Electron Microscopy (SEM) of the a-C films show a surface morphology with maximum grain size in the order of a few nanometers and the exclusion of macroparticles. INcreasing the nitrogen content of the CNX films increased the intensity of the X-ray Photoelecton Spectroscopy (XPS) C Is peak at 286.6 eV and formed a new peak at 285.6 eV which both can be associated with the carbon-nitrogen bond formation. Nanoindentaiton measurements showed that the hardness of the a-C films increased after implanting nitrogen into them. these CNX films exhibited a hardness of 19 GP A.

Carbon nitride films were deposited on sapphire, silicon, molybdenum and quartz substrates using a filtered cathodic arc with a radio frequency (rf) inductively coupled plasma, Previous researchers have used the cathodic arc but obtained low concentrations of nitrogen in their films. the addition of the rf coils was used to enhance dissociation of molecular nitrogen in the vicinity of the substrate. the resultant films were analyzed for chemical bonding and composition by several methods including Electron Energy Loss Spectroscopy (EELS), augei Electron Spectroscopy (AES), and infrared spectroscopy (IR). EELS and IR provided bonding information and showed that the films were largely composed of sp2 bonding and contained carbon-nitrogen double bonds, respectively. also, chemical composition of the films was determined using aES, IR and EELS.

In this study a high N2 pressure has been used to enhance the N incorporation into CN films produced by a shock plasma deposition method. auger spectroscopy indicates that increasing the nitrogen pressure from 0.1 atm to 10 atm results in an increase of nitrogen incorporation into CN films to a maximum of 43 at.%. Nitrogen distribution varies across the surface of the deposit, showing an increase of nitrogen content with depth in the center of the deposition and a decrease with depth at points away from the center. SEM and optical microscopy indicate that under increased nitrogen pressure the grain structure becomes finer. Raman spectra contain sharp peaks characteristic of a distinct crystalline CN phase. TEM diffraction patterns for the films produced under N2 pressure in the range of 0.05-0.1 atm unambiguously show the presence of micron-sized crystals displaying a cubic symmetry, and not the predicted β-Si3N4 type structure. PEELS data suggest that in the crystalline phase a significant fraction of the nitrogen atoms have sp2 trigonal bonds and there is a significant degree of sp3 character for the carbon atoms.

Using a specific combination of energetic and chemical processes we have grown homoepitaxial diamond on and lifted it off of a type Ia natural C(100) crystal. Before growth, the C(100) crystal is exposed to a self implant of 190keV energy and dose of 1E16 cm-2. Low temperature (~600°C) homoepitaxial diamond growth conditions were used that are based on water-alcohol source chemistries. To achieve layer separation (lift-off), samples were annealed to a temperature sufficient to graphitize the buried implant-damaged region. Contactless electrochemical etching was found to remove the graphite, and a transparent synthetic (100) single crystal diamond plate of 17.5μm thickness was lifted off. This free-standing diamond single crystal plate was characterized and found to be comparable to homoepitaxial films grown on unimplanted single crystal diamond.

Chromium containing amorphous hydrogenated carbon films (a-C:H/Cr) were prepared in a process that combines rf plasma activated chemical vapor deposition of methane and magnetron sputtering of a chromium target. During the deposition the silicon substrates were kept at 200°C and dc biased at -200 V in order to obtain films with high chemical stability which is required for the application as solar selective surfaces. the films with different Cr concentrations (5 to 49 at.%) were characterized by in situ x-ray photoelectron spectroscopy (XPS). Up to 40 at.%, chromium proves to be built into the cermet-like films in the form of chromium carbide clusters. above 40 at.%, chromium is partly metallic. a modification of the a-C:H matrix in the vicinity of the chromium carbide clusters has been observed.

Aluminum oxynitride films, 1 μm thick, are deposited onto glass substrates by planar magnetron sputtering from an alumina target in a mixture of nitrogen and argon. one set of films is deposited onto glass substrates that are heat sunk to a holder, whose temperature is held below 100°C. a second set of films is deposited onto glass substrates that are mechanically clamped to a holder, whose temperature is allowed to rise up to 250°C. Characterization by continuous indentation testing, secondary electron microscopy, and x-ray diffraction reveals significant differences in mechanical properties and surface structure between the two sets of films. Films deposited with holder cooling have a smooth surface and no evidence of crystallinity; films deposited without holder cooling have etch pits on their surface that vary with position across the substrate. the later films show crystallinity and have twice the hardness and a 60% greater elastic modulus.

A high-intensity ion beam (500 keV, current density 60 - 200 a/cm2, power density (0.25 - 1) • 108 W/cm2, pulse duration 60 ns, pulse repetition rate 4-6 mur-1) was used to deposit thin metal and carbon films by evaporation of respective targets. the instantaneous deposition rate was 0.6 - 5 mm/s. the films were examined using transmission electron microscopy and transmission electron diffraction. the metal films had a poly-crystalline structure with the grains measuring from 20 to 100 nm, the lower the melting point the greater the grain size. the carbon films contained 25 - 125 nm diamonds. the ablation plasma was studied employing methods of pulsed spectroscopy.

We demonstrate a novel technique for in situ observation of the chemical vapor deposition of high purity gold using ethyl(trimethylphosphine)gold(I). an environmental transmission electron microscope with 3.8 eV resolution was used to observe and compare the growth of the material with or without electron beam irradiation (120 keV) with Si (100) substrate temperatures ranging from 125-200 °C. Typical precursor pressures of 10-4 Torr and E-beam irradiation resulted in rapid growth of virtually continuous gold films. thermal deposition without the beam resulted in low nucleation densities, low deposition rates, and island-like growth. Images and diffraction patterns acquired during the deposition process indicated polycrystalline gold and elemental analysis at the nanometer scale showed that the films had excellent chemical purity. atomic force microscopy was also used to investigate the three dimensional morphology of the materials. the most notable result of the deposition process is the dramatic enhancement of the growth rate due to the beam irradiation.

We have used an electron cyclotron resonance enhanced plasma system to deposit films from methyl alcohol at a pressure of 1.00 Torr. Depositions occurred on silicon substrates at temperatures from 550 - 750 °C. Film morphology was examined using SEM. Structural characterization was conducted using Raman spectroscopy and x-ray diffraction. Based on these analyses, certain trends in film quality as a function of deposition temperature were determined.

MD simulations have been employed to investigate damage processes near surfaces during keV bombardment of metal targets. For self-ion implantation of au, Cu, and Pt in the range of 5-20 keV, we have found that the proximity of the surface leads to significantly more damage and atomic mixing in comparison to recoil events occurring in the crystal interior. IN some cases, large craters are formed in a micro-explosive event, while in others a convective flow of atoms to the surface creates adatoms and leaves dislocations behind. Both the amount damage created in the surface and its morphology depend sensitively on the details of the energy deposition along individual ion trajectories. the results of these simulations will be summarized and compared to recent scanning tunneling microscopy studies of individual ion impacts in Pt and Ge.

Several studies have shown that the surface morphology can be smoother during simultaneous ion bombardment and growth than during growth alone, however, the atomistic mechanism responsible for the smoothing effect has been difficult to determine. We have developed Monte Carlo simulations of growth and defect diffusion to model the interaction between growth atoms and ion-induced defects and to present a simple atomistic mechanism that describes the effects of low-energy ion bombardment during ion-assisted growth of germanium. Measurements of ion-induced point defect production indicate that a large number of defects exist only temporarily on the surface at typical growth temperatures, because the defects have sufficient mobility to recombine and annihilate. We propose that this ion-induced transient defect population plays a significant role in modifying the dynamic surface morphology. the simulations support a surface smoothing mechanism that involves the destabilization of adatom islands by the transient ion-induced defects. the optimum simulated steady-state surface morphology can be achieved with ion-induced defect production rates less than or equal to 10 defects/ion. We find that low-energy ion bombardment during growth effectively lowers the temperature at which step-flow growth can be achieved.

The growth mechanisms for the deposition of hydrocarbon films (C:H-films) from a methane electron cyclotron resonance (ECR) plasma are investigated by means of in-situ ellipsometry. Ion bombardment during plasma-enhanced chemical vapor deposition of hydrocarbon films mainly governs the properties of the films and the total growth rate. the role of ions for the growth rate and the film properties is discussed in this paper. Films were deposited with varying RF-bias, resulting in a DC self-bias ranging from floating potential up to 100 V. the ion-induced modification of the film properties was investigated by a new technique using a double layer consisting of a polymer-like film with low optical absorption and a hard carbon film with high absorption on top. the interface between these layers was analysed after deposition by a layer-by-layer etching in an oxygen plasma at floating potential. From these data it is possible to determine with high accuracy the range of the ion-induced modification of the optical properties in the underlying polymer-like film. the thickness of this modified layer ranges from 6 Å at 30 V self-bias to 40 Å at 100 V self-bias, which is consistent with the range of hydrogen ions in polymerlike films as calculated by the computer code TRIM.SP.

Based on the presented results, the growth of C:H-films and the resulting film properties can be modelled by the growth at activated sites at the film surface. these activated sites are represented by dangling bonds, induced by the ion bombardment. they also show up in the ellipsometric results during the deposition of C:H-films by a change of the optical response of the film surface.

Direct ion beam sputter deposition of alN is studied using both pure nitrogen and a 75% N2/25% H2 mixture as the feed gas for the ion gun. the chemical characteristics of these films are probed using infrared spectroscopy and chemical etching. the presence of al-N2 species is associated with reactive and highly defective films. the presence of NHX species increases by several orders of magnitude the rate at which alN film are etched by base. However, stoichiometric and low defect alN films prepared by depositing alN:H onto substrates heated to 200 °C have reactivities similar to the best alN films produced in the absence of hydrogen.

In this paper, we report laser-assisted chemical beam epitaxy (CBE) of GaAs using triethylgallium (TEGa), tris-dimethylaminoarsenic (TDMAAs), and an ar ion laser operating at visible or ultraviolet (UV) wavelength. the laser-assisted growth with TDMAAs, compared to as4 or asH3, shows a wider range of growth enhancement at low substrate temperatures. Unlike CBE of GaAs without laser irradiation, laser-enhanced GaAs growth rate was found to be constant as the V/III incorporation ratio changes. by using diiodomethane (CI2H2) as a dopant gas, the GaAs films with laser irradiation show a much higher hole concentration than those grown simultaneously without laser irradiation at substrate temperatures from 460-530°C. Laser irradiation was also found to enhance silicon incorporation at low temperatures. Photothermal effects are responsible for laser-enhanced growth and silicon doping, but the wider temperature window in laser-enhanced growth and the laser-enhanced carbon incorporation are caused by additional photocatalytic or photochemical effects.

Tin doped indium oxide (ITO) films were deposited on glass substrates by rf reactive magnetron sputtering using a metallic alloy target (In-Sn, 90-10). the post-deposition annealing has been done for ITO films in air and the effect of annealing temperature on the electrical, optical and structural properties of ITO films was studied. It has been found that the increase of the annealing temperature will improve the film electrical properties. the resistivity of as-deposited film is about 1.3 х 10-1 Ω*cm and decreases down to 6.9 х 10-3Ω*cm as the annealing temperature is increased up to 500 °C. IN addition, the annealing will also increase the film surface roughness which can improve the efficiency of amorphous silicon solar cells by increasing the amount of light trapping.

We have recently demonstrated a new implantation technique called SPIMOX (separation by plasma implantation of oxygen) to synthesize silicon-on-insulator structures using plasma immersion ion implantation (PIII) process. the implantation is performed by applying a large negative bias to a Si wafer immersed in an oxygen plasma created by an ECR source. Since the technique has no mass analysis, coexistence of O+ and O2+ ions in oxygen plasma can cause a non-Gaussian profile of the as-implanted oxygen distribution. We observed that during post-implantation annealing, the ripening process of the oxide precipitates depends on depth and concentration of the oxygen peaks. IN addition, implanted oxygen can migrate towards the Si surface during annealing, preventing a continuous buried oxide layer formation. IN this paper, we report our observation on the effect of the implantation profile on the competitions between internal oxidation at different depths and between internal and surface oxidation processes. With an additional He implantation, we demonstrate that the nucleation of oxide precipitation can be enhanced.

Carbon Nitride (CNX) films have been grown by ion-assisted pulsed-laser deposition (IAPLD). Graphite targets were laser ablated while bombarding the substrate with ions from a broad-beam Kaufman-type ion source. the ion voltage, current density, substrate temperature, and feed gas composition (N2 in ar) have been varied. the resultant films were characterized by Raman, Fourier transform infrared (FTIR), and Rutherford back scattering (RBS) spectroscopy.

Samples with -30% N/C ratio have been fabricated. the corresponding Raman and FTIR spectra indicate that nitrogen is incorporated into the samples by insertion into sp2-bonded structures. a low level of C=N triple bonds is also found. as the ion current and voltage are increased with a pure ar ion beam, Raman peaks associated with nanocrystalline graphite appear in the spectr A. adding low levels of nitrogen to the ion beam first reduces the Raman intensity in the vicinity of the graphite disorder peak without adding detectable amounts of nitrogen to the films (as measured by RBS). at higher nitrogen levels in the ion beam, significant amounts of nitrogen are incorporated into the samples, and the magnitude of the "disorder" peak increases. by increasing the temperature of the substrate during deposition, the broad peak due mainly to sp2-bonded C-N in the FTIR spectra is shifted to lower wavenumber. This could be interpreted as evidence of single-bonded C-N; however, it is more likely that the character of the sp2 bonding is changing.

Aluminum nitride (AlN) thin films have been synthesized by ion-beam assisted deposition method. Film deposition has been performed on the substrates of silicon single crystal, soda-lime glass and alumin A. the influence of the substrate roughness on the film roughness is studied. the substrate temperature has been kept at room temperature and 473K and the kinetic energy of the incident nitrogen ion beam and the deposition rate have been fixed to 0.5 keV and 0.07 nm/s, respectively. the microstructure of the synthesized films has been examined by X-ray diffraction (XRD) and the surface morphology has been observed by atomic force microscopy(AFM). IN the XRD patterns of films synthesized at both room temperature and 473K, the diffraction line indicating the alN (10*0) can be discerned and the broad peak composed of two lines indicating the a1N (00*2) and a1N (10*1) planes is also observed. aFM observations for 100 nm films reveal that (1) the surface of the films synthesized on the silicon single crystal and soda-lime glass substrates is uniform and smooth on the nanometer scale, (2) the average roughness of the films synthesized on the alumina substrate is similar to that of the substrate, suggesting the evaluation of the average roughness of the film itself is difficult in the case of the rough substrate, and (3) the average roughness increases with increasing the substrate temperature.

Two types of systems for in situ transmission electron microscopy analysis of ion-beam etching, ion-beam sputtering and ion-beam assisted deposition are reported. their design, operational features and some applications are presented. Radiation-stimulated diffusion in Mo-Si heterostructure, early growth of ion-beam sputtered in-Sn, in-Sn-O, ZnS:Mn films and recrystallization of ln-Sn-O films during vacuum post-annealing are studied.