bluuebunny/crossref_metadata_2025_split huggingface dataset:
Surface Decomposition Kinetics of Organosilane Precursors to Silicon Carbide
Authors: Han Bin , Hudson John B. , Interrante Leonard V. 
Published: March 2011

ABSTRACTReactive molecular beam scattering techniques with mass spectrometric detection have been used to characterize the kinetics and mechanism of the decomposition of two 1,3-disilacyclobutane precursors to SiC on the Si(100) surface to yield SiC and gas-phase byproducts. Both compounds adsorb and desorb without dissociation at ambient temperature. Reaction probability increases with increasing surface temperature to a maximum exceeding 0.8 at 1100 K. Both compounds yield large quantities of gas-phase intermediates, while only one produces a significant yield of SiC in the initial collision. In situ and ex situ analysis of the SiC film indicate that it is stoichiometric SiC. A combination of mass spectrometric detection with time of flight analysis of surface reaction products permits formulation of a reaction scheme involving a multistep surface decomposition sequence.
Ab Initio Computation of Thermochemistry and Kinetics in the Oxidation of Gas Phase Silicon Species
Authors: Zachariah Michael R. , Tsang Wing 
Published: March 2011

ABSTRACTAb initio molecular orbital calculations coupled to RRKM reaction rate theory have been conducted on some important reactions involved in the oxidation of silane in a high-temperature/high H2O environment. The results indicate thatH2O acts as an oxygen donor to SiH2 to form H3SiOH or SiH2O. Subsequent reactions involve the formation of (HSiOOH, H2Si(OH)2,:Si(OH)2 or SiO). In turn SiO polymerizes into planar rings, without an activation energy barrier. A list of calculated thermochemical data are also presented for a number of equilibrium species.
Chemical Vapor Deposition of SiO2 from Ozone-Organosilane Mixtures near Atmospheric Pressure
Authors: Guinn K. V. , Mucha J. A. 
Published: March 2011

ABSTRACTThe kinetics of deposition of SiO2 by the reaction of tetramethylsilane (TMS) with ozone (O3) has been studied over the temperature range 180 – 380° C and compared with available data for the same process using tetraethoxysilane (TEOS). Both processes exhibit the same activation energy (17 kcal/mole) below 300 ° C which falls-off at higher temperatures due to transport limitations. Transition from first- to zero-order kinetics occurs with increasing concentrations of TMS and O3, which gives an overall O3/TMS consumption ratio of 10 at 258° C and5 at 325° C. TEOS is estimated to be 5 times more reactive than TMS above 300° C and over 10 times more reactive in the kinetically-limited regime below 300° C. Results suggest that O3-induced SiO2 deposition proceeds via surface reactions and is limited by heterogeneous decomposition of ozone.
Effect of Thermal Degradation on the Adhesion of Polyimide'Silicon Interface
Authors: Chu Y Z. , Durning C. J. 
Published: March 2011

ABSTRACTThe object of this work is to identify the most important structure features in the bonding of polyimide/silicon during the curing anddegradation. An essential tool for this work is a quantitative adhesion measurement which can relate the macroscopic adhesion strength to the microscopic interfacial structures. We apply the blister test forthis purpose. In particular, the test is applied to examine the effect of thermal history on the adhesion of PMDA-ODA polyimide on siliconsurface. Our studies show that the test is accurate and sensitive. The adhesion data reveal that increases in adhesion strength coincide with the formation of certain thermal degradation products as revealedin the earlier thermal degradation studies. This suggests a mechanismfor increases in adhesion strength with curing temperature, based on chemical and physical modification of the interface.
Chemical Spray Pyrolysis of Complex Thin Solid Films
Authors: Bates Clayton W. , Varner Elizabeth B. , Alshvang Svetlana , Summers Keith 
Published: March 2011

ABSTRACTChemical spray pyrolysis (CSP) is a technique in which compounds of the constituents of the thin film to be fabricated are dissolved in an aqueous solution which is subsequently sprayed onto a heated substrate using nitrogen as the atomizing gas. At relatively low substrate temperatures (150–400°C) chemical reactions take place in which film formation of the desired compound occurs concomitantly with the release of volatile chemical reactants. The technique has advantages that include: (1) simplicity, (2) low cost and simple equipment, (3) the ability to prepare films over large areas with various shapes with relative ease and (4) the possibility of varying the physical properties through chemical means in known ways at modest temperatures. Results on the preparation of CuInSe2 which is a defect dominated semiconductor of technological interest are presented. Both n- and p- type materials were prepared with resistivities varying from 10−2 – 104 ohm-cm illustrating the use of the control of solution chemistry to produce films with reproducibly controlled properties.
Low Pressure Diamond Growth Using a Secondary Radical Source
Authors: Hukka Terttu I. , Rawles Robin E. , D'Evelyn Mark P. 
Published: March 2011

ABSTRACTA novel method for chemical vapor deposition and atomic layer epitaxyusing radical precursors under medium vacuum conditions is being developed. Fluorine atoms are generated by thermal dissociation in a hot tube and abstract hydrogen atoms from precursor molecules injected immediately downstream of the source, generating radicals with completechemical specificity. The radical precursors are then transported to the growing substrate surface under nearly collision-free conditions. To date we have grown diamond films from CCl3 or CH3 radicals together with atomic hydrogen, generated by injecting CHCI3 or CH4 and H2 into the F atom stream at reactor pressures between 10−4 and 10−2 Torn This approach should be ideal for low-temperature growth and atomic layer epitaxy: growth rates remain relatively high because activation energies for radical reactions are typically small and because the cycle times for atomic layer epitaxy can be reduced to die msec range by fast gas-stream switching, and contamination and segregation are minimized by keeping the surface “capped” by chemisorbed intermediates.
Surface Spectroscopic Studies of the Initial Stages of Diamond Growth on Si(100)
Authors: Jackman Richard B. , Chua Lye Hing , Foord John S. 
Published: March 2011

ABSTRACTThe interaction of hot filament “activated” methane and hydrogen with Si(100) surfaces has been probed in situ for the first time, using Auger electron and thermal desorption spectroscopies. It is shown that hot filament activation of methane results in thechemisorption of acetylene and ethylene on Si (100). Atomic hydrogen drives a range of surface reactions within the adsorbed phases formed. In particular hydrogen abstraction is observed which results in the efficient conversion of ethylene to adsorbed acetylene, and further reactions take place between atomic hydrogen, acetylene and C1 species, resulting in the formation of C3 hydrocarbon species. The implications of this work for diamond film growth are considered, and die results are used to develop a model to describe die growth of sp3 hybridised hydrocarbon chains on the Si surface.
Deposition Rate Monitoring using Laser Induced Fluorescence
Authors: Reiley Timothy C. , Marinero Ernesto E. , Notarys Harris 
Published: March 2011

ABSTRACTUltra thin films (< 10 nm) prepared using sputtering or other deposition techniques are becoming more technologically important, with promise of increased importance in the future, particularly in certain magnetic structures. For example, giant-magnetoresistive structures may incorporate individual layers having a thickness < 1 nm. Such a small thickness is commonly associated with relatively short deposition times (∼10 s) and may place limits on the reproducibility and accuracy of the conventional techniques for in situ thickness monitoring or integrated rate monitoring. Experiments have been performed to use laser induced fluorescence (LIF) as a rate monitoring technique for ultra thin films. An RF diode sputtering system was combined with a YAG-pumped, frequency-doubled dye laser to monitor the deposition rale of copper over a range of conditions. When coupled with an absolute calibration reference, the LIF signal gave a reproducible, well-behaved output over a range of pressure and temperature. The technique is potentially advantageous for depositions where rapid (∼1 s) measurements are needed. LIF is also projected to be a valuable tool for detecting very low deposition rates, and it offers the potential of sensitive, real time, spatially-resolved detection in time regimes extending to the nanosecond regime.
Bimetallic Precursors for Ferroelectric Thin Films; Molecular Control of Stoichiometry
Authors: Vaartstra Brian A. 
Published: March 2011

ABSTRACTThe application of ferroelectric oxides in microelectronic and optical devices is critically dependent upon methods to deposit high quality thin films. A major factor influencing the film quality is non-ideal metal stoichiometries caused by process variables. Materials such as PbTiO3 and POZrO3 are well suited for stoichiometric control via molecular precursors having the required metal ratio, eliminating many process variables. Bimetallic precursors for the deposition of lead titanate and PZT thin films have been designed in order to optimize control over the metal stoichiometry. This is accomplished by the synthesis of volatile metalorganic compounds having a 1:1 ratio of Pb:Ti or Pb:Zr. Synthesis and characterization of these novel compounds are presented, and viability for metalorganic chemical vapor deposition (MOCVD) is discussed, based upon decomposition and volatility studies.
Mass Spectrometric Thermal Evolution of Novel Indium Metalorganic Precursors for MOCVD
Authors: Bruno G. , Capezzuto P. , Cicala G. , Losurdo M. , Rossetto G. , Porchia M. , Zanella P. 
Published: March 2011

ABSTRACTThe thermal behaviour of dialkylindium-dialkylamides R2InNR/2 (R,R'=Me, Et) and dialkylindium-azolides R2lnNR' (NR'=Pyrrole, Pyrazole) has been examined by a mass spectrometric thermal evolution technique, in the temperature range 30–400°C. Data on volatility, identity of gasified molecules, threshold temperature and products of the decomposition processes are reported and discussed.
Selective Growth of Polycrystalline Diamond Thin Films
Authors: Ramesham R. 
Published: March 2011

ABSTRACTMicrowave plasma assisted CVD is employed to grow diamond films using a gas mixture of H2 and CH4on various substrates. Diamond has a tendency not to nucleate growth on mirror-smooth finished substrates irrespective of the substrate type (except single crystal diamond). We have developed various processes to enhance the nucleation density of the diamond substantially by damaging or seeding the surface of the substrates. Several process techniques such as 1. silicon nitride and silicon dioxide process, 2. ultrasonic agitation process, 3. selective seeding of diamond by electroplating of Cu, 4. patterning of diamond films by air-microwave plasma etching, etc., were developed to achieve the patterns of diamond on various substrates. Selective growth of doped diamond and low temperature growth of diamond for microelectronic applications have also been achieved by using the above processes (1 and 2). Details on selective diamond growth processes and the morphology of as-deposited selective diamond by SEM are presented.
Pyrolysis Studies and Deposition of Sb Films Using the Novel Omvpe Source (I-Pr)2 SbH
Authors: Gedridge Robert W. , Lee Kenneth E. , Lowe-Ma Charlotte K. 
Published: March 2011

ABSTRACTThe novel antimony source compound di-isopropylantimony hydride, (i-Pr)2 was synthesized and evaluated for use as a volatile Sb-source compound for low temperature growth of Sb-containing semiconductor materials. (i-Pr)2SbH was pyrolyzed in a horizontal atmospheric pressure organometallic vapor phase epitaxy (OMVPE) reactor using Arand H2 as carrier gases. The gaseous exhaust products were analyzed by a residual gas analyzer. Complete pyrolysis of (i-Pr)2SbH in our OMVPE reactor occursaround 300°C and 350°C in Ar and H2, respectively. A comparison between the pyrolysis temperatures and pyrolysis byproducts with respect to a proposed decomposition mechanism of (i-Pr)2SbH is presented. Sb films were grown on Si(100) andSi(111) as low as 200° C. The Sb films were analyzed by Auger and X-ray diffraction. These polycrystalline Sb films were free of detectable carbon by AES. X-ray diffraction data indicated that these Sb films were highly oriented in the [000L] direction.
High Quality P-Doped μc-Si:H Films as Obtained by low Temperature Lpcvd of Disilane
Authors: Manfredotti C. , Fizzotti F. , Amato G. , Boarino L. , Abbas M. 
Published: March 2011

ABSTRACTBoth B- and P- doped silicon films deposited by Low Pressure Chemical Vapor Deposition (LPCVD) at 300 °C (p-type) and 420 °C (n-type) have been characterized by optical absorption, Photothermal Deflection Spectroscopy (PDS), resistivity, Elastic Recoil Detection Analysis (ERDA), Transmission Electron Microscopy (TEM), Convergent-Beam Electron Diffraction (CBED) and Raman spectroscopy measurements. P-doped films, deposited at large PH3 flux rates, show a high degree of microcrystallinity, indicating that P activates the nucleation process even at low temperatures. In this case, values of activation energy of resistivity as low as 0.007 eV were obtained. Both TEM and RAMAN results confirm a volume percentage of micro crystallinity above 30%. On the contrary, B-doped samples are not microcrystalline at least in the doping range investigated, and show a behaviour not different from samples deposited by PECVD.
Si2p Core Level Absorption and Photoemission Spectra of Porous Si
Authors: Nakashima Hisao , Inoue Koichi , Maehashi Kenzo 
Published: March 2011

ABSTRACTSi2p core level absorption and photoemission spectra are taken for different porous Si layers using synchrotron radiation, toknow the electronic structures of porous Si. The core level absorption spectra show the high energy shift of the conduction band which correlates with the photo-luminescence blue shift. The oxidation states of porous Si are clarified from the photoemission spectra.
Visible Luminescence from Porous Silicon and Siloxene: Recent Results
Authors: Fuchs H. D. , Rosenbauer M. , Brandt M. S. , Ernst S. , Finkbeiner S. , Stutzmann M. , Syassen K. , Weber J. , Queisser H. J. , Cardona M. 
Published: March 2011

ABSTRACTThe optical properties of porous Si (p-Si) are compared to those of siloxene and its derivatives in order to gain more insight into the mechanism of the luminescence observed in p-Si. We report new results of photoluminescence (PL), photoluminescence excitation (PLE), time-dependent and pressure-dependent photoluminescence, and optically detected magnetic resonance (ODMR). Important information about the structural, electronic, and microscopic nature of the two classes of materials are deduced from these experiments. Annealed siloxene and p-Si show very similar properties, suggesting that siloxene-related structures, e.g. electrically isolated Si6-rings, might be responsible for the luminescence in p-Si. The Si-planes in as-prepared siloxene, with their green luminescence, are metastable and are readily oxidized into red-luminescent siloxene configurations.
Characterization of Porous Silicon Layers by Reflectance Spectroscopy
Authors: Theiβ W. , Grosse P. , Münder H. , Lüth H. , Herino R. , Ligeon M. 
Published: March 2011

ABSTRACTThe characterization of porous silicon layers by optical reflectance spectroscopy in the infrared, visible and UV is presented. A fit of simulated to measured spectra is used to interprete the experimental results. We stress that the microgeometry of the porous system determines the optical properties to a large extent and must be taken into account in a correct way in order to achieve reliable results.
Intense Visible Luminescence from Thermally-Oxidized Porous Silicon
Authors: Miyazakj S. , Shiba K. , Sakamoto K. , Hirose M. 
Published: March 2011

ABSTRACTPhotoluminescence from porous silicon oxidized at 800 or 900°C in an N2 +O2 gas mixture has been investigated. The ideal passivation of the porous Si surface with thermally grown oxide results in stable, intense visible-light emission. The steady-state and time-resolved luminescence measured as functions of temperature and excitation power have indicated that a possible pathway for the light emission is the radiative recombination through localized states.
Degradation of Porous Si Layers Caused by Thermal Treatment
Authors: Münder H. , Berger M. G. , Frohnhoff S. , Lüth H. , Rossow U. , Frotscher U. , Richter W. 
Published: March 2011

ABSTRACTPorous Si Alms formed on different p-doped substrates are studied by Raman spectroscopy, photoluminescence, and spectroscopic ellipsometry. Due to a thermal treatment the morphology is changed. A reduction in the number of nanocrystals with diameters below 30Å is found. It is shown that the photoluminescence is caused by the formation of small nanocrystals and that the effect of amorphous Si as a basic mechanism can be ruled out. The strain which must be taken into account for the interpretation of the Raman spectra decreases with increasing heating temperature.
A Unity Quantum Efficiency Photodiode using Porous Silicon Film
Authors: Zheng J. P. , Jiao K. L. , Shen W. P. , Anderson W. A. , Kwok H. S. 
Published: March 2011

ABSTRACTA highly sensitive photodiode was fabricated with a metal-porous silicon junction. The spectral response was measured for the wavelength range from 400 nm to 1.075 μm. It was demonstrated that close to unity quantum efficiency could be obtained in the wavelength range of 630 to 900 nm without any anti-reflective coating. The detector response time is about 2 ns for a 9 volts reverse bias. The acceptance angle of photodiode is 2 times better than that of conventional Si detectors. The uniformity and stability were also studied. Possible mechanisms are discussed.
The Depth Dependence of Photoluminescence and Electrolytic Electroluminescence in Porous Silicon Films
Authors: Beale M. I. J. , Cox T. I. , Canham L. T. , Brumhead D. 
Published: March 2011

ABSTRACTThe depth dependence of the photoluminescence (PL) spectrum, both in terms of intensity and wavelength of the peak, is correlated with the electrochemical and chemical processes occurring during the formation of the porous silicon. The depth dependence of the intensity of the electroluminescence (EL) under both anodic bias and cathodic bias, in solutions containing 1M H2SO4 and 0.1M Na2S2O8, is found to be identical with that of the PL. These observations strongly suggest that the silicon skeleton is highly conductive during electrolytic EL, in marked contrast to its high resistivity in air. Strong evidence is provided linking the electrolytic EL to the PL. We extend the quantum confinement based model for PL to the case of electrolytic EL.
Crystallinity and Optoelectronic Properties of μc-SiC:H
Authors: Demichelis F. , Crovini G. , Osenga c. , Pirri C. F. , Tresso E. , Boarino L. 
Published: March 2011

ABSTRACTSamples of μc-Si1-xCx:H with different degree of crystallinity and different carbon content were deposited by Plasma Enhanced Chemical Vapor Deposition and characterized by means of optical, electrical and structural measurements. The correlation between the degree of crystallinity and the mechanism of conductivity and optical transitions in both amorphous and crystalline phases and at the crystalline-amorphous interfaces is reported and discussed in terms of a band structure model.
Nanocrystalline Ge Synthesis by Reduction of Si1-xGexO2 Formed by High Pressure Oxidation
Authors: Paine David C. , Caragianis Christine , Kim Tae Young , Shigesato Yuzo 
Published: March 2011

ABSTRACTNanocrystalline Ge suitable for photoluminescence studies was synthesized from hydrothermally oxidized alloys of Si60Ge40 using steam at 25 MPa and 475°C. Annealing in either an inert atmosphere (UHP N2) or in flowing forming gas (80:20 N2:H2) results in Ge precipitation. In the first case the Ge precipitates are large and concentrated in the bottom portion of the oxide and result from Si reduction of GeO2. In the case of flowing forming gas the Ge precipitates are distributed diroughout die oxide and are formed by reaction between H2 and GeO2. The precipitated samples were analyzed using Raman spectroscopy and cross sectional TEM. Preliminary photoluminescence data reveal that oxide samples excited by the 325 nm line of a HeCd laser after annealing in H2 at both 750 and 800°C for 30 min show strong visible luminescence while unannealed samples do not.
Separation of Nucleation and Growth Processes of Nanocrystalline Silicon by Hydrogen Radical Treatment of Hydrogenated Amorphous Silicon
Authors: Otobe Masanori , Oda Shunri 
Published: March 2011

ABSTRACTWe have investigated nucleation and growth mechanism of nanocrystalline silicon (nc-Si) based on the experimental observation of plan-view transmission electron microscopy. Nanocrystalline Si has been prepared by hydrogen radical annealing of hydrogenated amorphous silicon (a-Si:H) layer, which is deposited on hydrogen radical treated a-Si:H buffer layer. Nanocrystallization depends critically upon hydrogen radical annealing time and the thickness ofa-Si:H layer. Hydrogen radicals play important roles in both nucleation and growth processes in a different way. Growth of nc-Si can be explained by “hydrogen diffusion model”, in which hydrogen radicals diffusing through a-Si:H layer to interface cause nanocrystallization. Our results imply that nuclei for nc-Si are generated at the interface between a-Si:H and under layer when treated by hydrogen radicals.
The Micro-Structure and Electron Conduction Mechanism of Hydrogenated Nano-Crystalline Silicon Films
Authors: He Yuliang , Chu Yiming , Lin Hongyi , Qin Guoguang 
Published: March 2011

ABSTRACTThe hydrogenated nano-crystalline silicon (nc-Si:H) films have been deposited with PECVD method.1–2 The micro-structure of these films has been studied by TEM and HREM. The PECVD nc-Si:H films show fiber texture structure which is exceptional compared with the nano-size materials made by the method of compressing granules method. The fractal dimention of this texture structure has been calculated with a Fourier filtered image. The relationshisps between conductivity and temperature and micro-structure has also been studied and the mechanism of electron conduction is discussed.
Electrical Properties of Boron-Doped μc-Si:H Prepared by Reactive Magnetron Sputtering from c-Si Targets
Authors: Turner W. A. , Williams M. J. , Chen Y. L. , Maher D. M. , Lucovsky G. 
Published: March 2011

ABSTRACTWe discuss the preparation and electrical properties of B-doped μc-Si:H thin films prepared by reactive magnetron sputtering in a hydrogen containing ambient. The B-concentration, and hence the dark conductivity, have been varied by controlling the rf power supplied to two sputtering targets, one, of undoped c-Si, and the other of B-doped c-Si. Films deposited from either target alone display dark conductivity activation energies of approximately 0.5 eV due to Fermi level pinning by native donorlike defects and B-doping for samples prepared from the undoped and B-doped targets, respectively. Films deposited by simultaneously sputtering undoped and B-doped targets display activation energies which first increase to approximately 0.7 eV and then decrease as the fraction of power supplied to the B-doped target is increased. For the combination of deposition parameters used, the cross over point between B-compensated, n-type films, and B-doped p-type films occurs for powers of 50 W supplied to the B-doped target and 100 W to the undoped target. B-compensated samples display trends in photoconductive properties essentially identical to results for μc-Si:H samples prepared by remote plasma CVD. However, IR studies indicate that the material shows significant post-deposition oxide formation. TEM studies confirm the existence of a low-density, porous network. Work is underway to optimize the structural aspects of this material.