bluuebunny/crossref_metadata_2025_split huggingface dataset:
On the Contribution of a Nitrogen-Related Defect in the Nexafs Spectra of Thin Si3N4Films
Authors: Paloura E. C. , Knop A. , Dobler U. , Holldack K. , Logothetidis S. 
Published: March 2011

ABSTRACTThin amorphous SiN films grown on Si are studied with Near Edge X-Ray Absorption Fine Structure (NEXAFS). The NEXAFS spectra of N-rich films are characterized by a strong resonance line (RL) at the onset of the N K- edge. The intensity of the RL in N-rich films increases with the N/Si ratio, while the same RL is detected in the NEXAFS spectra of stoichiometric SiN films subjected to damage with Ar+ion bombardment. The RL is attributed to a N-related defect which is strongly localized in a pure 2p orbital. The RL, which is identified as a bulk nitride property, can be annealed out at temperatures higher than the growth temperature. It is proposed that the annealing process of the RL, which is characterized by an activation energy of 0.87eV, is due to Si-N bond formation, where the Si atoms are provided by the stressed SiN/Si interface.
Anomalous Behavior of Semi-Insulating Silicon Rich Amorphous Silicon Nitride
Authors: Bernstein J. B. , Gleason E. F. , Wetsel A. E. , Liu E. Z. , Wyatt P. W. 
Published: March 2011

ABSTRACTSilicon rich PECVD amorphous silicon nitride has been used as an inter-level metal dielectric for making laser programmable connections on restructurable VLSI. There is an apparent Schottky barrier characteristic that has a 0.11 eV lower barrier for Ti than for Al. The stoichiometry was analyzed using RBS and HFS, and found to contain approximately 55% Si, 25% N, and 20% H by atomic percentages. The optical bandgap is 2.01 eV as found by the Tauc method.The insulating behavior depends on time in an anomalous manner at applied fields greater than about 0.2 MV/cm, whereby the current increases with time for several secondsuntil it reaches an equilibrium value. The current decays in a normal charging manner at lower fields and in samples with insulating sub-layers between the electrodes and thenitride. When used as a gate dielectric, there is a long-time charging behavior that shifts the flat band voltage in the opposite direction of the applied stress. This shift is indicative of polarization within the dielectric. This behavior is similar to that of a reverse biased a-Si:H p-i-n diode.
Thermal Properties of Thin Films
Authors: Lambropoulos J. C. , Hwang S.-S. 
Published: March 2011

ABSTRACTWe summarize various measurements of the thermal conductivity of thin ceramic films which show that the thermal conductivity of thin films with thickness in the micron and sub-micron range may be up to two orders of magnitude lower than the thermal conductivityof the corresponding bulk solid. The reduction in the thin film effective thermal conductivity is attributed to the interfacial thermal resistance across the film/substrate interface.
Floating Temperature Deposition of Device Quality SiO2 Thin Films by DECR Plasma
Authors: Agius B. , Hugon M. C. , Jiang N. , Varniere F. , Plais F. , Pribat D. , Froment M. , Puech M. 
Published: March 2011

ABSTRACTLow temperature deposition of dielectric thin films is more and more used in very largescale integrated (VLSI) circuits. For this purpose, distributed electron cyclotron resonance (DECR) plasma appears to be a promising tool. The most interesting feature of this recent plasma is the high ion density (≈1011 cm−3) associated with low electronic temperature (2–3eV) and low energy species (20–30 eV). The purpose of this study is to discuss the effects of the reactant gas mixture composition (O2sol;SiH4) and the rf substrate bias power on the physical, chemical and electrical properties of DECR SiO2 films deposited at floating temperature (<100°C). Under optimum deposition conditions, the films show excellent characteristics, comparable to those obtained with thermal oxides grown at 850–1050°C.
Impact Ionization, Degradation, and Breakdown in SiO2
Authors: Dimaria D. J. , Cartier E. , Arnold D. 
Published: March 2011

ABSTRACTDestructive breakdown in silicon dioxide is shown to be strongly correlated to the oxide degradation caused by hot-electron-induced defect production and charge trapping ner the interfaces of the films. Two well defined transitions in the chargc-to-breakdown data as a function of field and oxide thickness are shown to coincide with the onset of mechanisms due to trap creation and impact ionization by electrons with energies exceeding 2 and 9 eV (the SiO2 bandgap energy), respectively. The temperature dependence of charge-to-breakdown is also shown to be consistent with that of these two defect-producing mechanisms.
Injection-Related Damage in Metal-Oxide-Silicon Tunnel Diodes
Authors: Farmer K. R. , Lundgren P. , Andersson M. O. , Engstrom O. 
Published: March 2011

ABSTRACTCurrent-voltage and conductance-voltage characterization is used to study high bias related “positive charge” in MOS tunnel diodes fabricated on p-type substrates. This charge effect appears to be associated with interface state levels that are located both throughout the band gap, and at a well-defined energy level roughly 0.3 eV above the silicon valence band edge. The well-defined state apparently acts as a tunnelingcenter communicating with the gate electrode and the silicon valence band. In addition, the first observation of high bias related charge is reported for tunnel diodes built on n-type substrates. This charge has positive character at low bias levels, transforming to net negative charge at high gate voltages.
Measurement of High Voltage Stress Induced Traps Inside Thin Silicon Oxide Films
Authors: Dumin D. J. , Maddux J. R. 
Published: March 2011

ABSTRACTAfter thin silicon oxide films were stressed at high voltages, two changes occurred in the current-voltage and transient current characteristics of the films. The low-level, pre-tunneling current rose and the transient decay of the current after removal of a voltage pulse changed from an exponential RC time constant decay to a very long decay that was characterized by a 1/t time dependence. Using an extension of the tunneling front discharge model, previously developed to describe the transient changes in the threshold voltages of transistors after avalanche injection or irradiation, the 1/t time dependence was derived. This 1/t transient discharge current was used to determine the density and distribution of the traps inside of the oxide after the high voltage stress. The technique and model used for determining the trap densities and distributions from the transient currents will be described. The model was used to describe the charging of traps in the oxide.
Detection of Hydrogen in Bulk and Thin Film Silicon Dioxide by Hydrogen Nuclear Magnetic Resonance
Authors: Levy D. H. , Gleason K. K. 
Published: March 2011

ABSTRACTHydrogen is a common impurity in silicon dioxide (SiO2) which can influence its optical and electronic properites. Here, nuclear magnetic resonance (NMR) is applied to study of hydrogen in these materials, despite their relatively low hydrogen content. We present results for bulk fused silica as well as thermally grown films of SiO2 on silicon. These experiments demonstrate the potential of solid state NMR for studying low hydrogen content film systems. In bulk fused silica, we have observed that although the majority of hydrogen is isolated, a small number of centers exist involving adjacent silanol pairs. These pairs react during high temperature annealing as well as during deep ultraviolet irradiation. Furthermore, the presence of these centers is related to the susceptibility of fused silica to radiation damage. The results obtained on the fused silica material are compared to SiO2 films on silicon. The NMR spectra and relaxation associated with thick (>1μm) wet SiO2 films are similar to those for the fused silica while the NMR data for thinner oxide more closely resembles those of surface water on silica gel.
Depth Profiling of Oxygen Vacancy Defect Generation in Buried SiO2
Authors: Stesmans A. , Vanheusden K. 
Published: March 2011

ABSTRACTOxygen-vacancy defects (E') generated at the surface of buried SiO2 layers formed by O+ implantation during the separation by implantation of oxygen (SIMOX) process have been studied by electron spin resonance (ESR) at 4.2 K. The E' damage was generated during exposure to a dc Ar glow discharge that produces defects predominantly in a surface layer of ≈100 Å thick, reaching local volume densities at the surface up to 8 × 1019 cm−3. This glow discharge exposure, alternated with step-by-step etch back, allowed mapping of a defect generation sensitivity depth profile of the buried oxide (BOX) layer, revealing a fairly uniform sensitivity with a strong decline towards the BOX/substrate interface. Besides the usual E' γ signal, the E'δj center — a delocalized variant of the E' center — has been newly observed in the BOX. Reoxidation of the BOX was observed to reduce the E' sensitivity close to that of regular dry thermal oxide (≥ 29 times lower), while the E'γ signal could no longer be generated, again similar to conventional thermal oxide. These data suggest a revision of the model for the E' defect. In general, the results strongly suggest that the buried oxide contains excess Si, exceedingly so near the BOX/substrate interface.
Quasi-Stoichiometric Silicon Nitride Thin Films Deposited by Remote Plasma-Enhanced Chemical-Vapor Deposition
Authors: Lucovsky G. , Ma Y. , He S. S. , Yasuda T. , Stephens D. J. , Habermehl S. 
Published: March 2011

ABSTRACTConditions for depositing quasi-stoichiometric silicon nitride films by low-temperature, remote plasma-enhanced chemical-vapor deposition, RPECVD, have been identified using on-line Auger electron spectroscopy, AES, and off-line optical and infrared, IR, spectroscopies. Quasi-stoichiometric films, by the definition propose in this paper, do not display spectroscopic evidence for Si-Si bonds, but contain bonded-H in Si-H and Si-NH arrangements. Incorporation of RPECVD nitrides into transistor devices has demonstrated that electrical performance is optimized when the films are quasi-stoichiometric with relatively low Si-NH concentrations.
Composition Analysis of RF Plasma-Deposited Amorphous Silicon Oxynitride Thin Films by Spectroscopic Phase-Modulated Ellipsometry
Authors: Campmany J. , Andujar J. L. , Canillas A. , Costa J. , Bertran E. 
Published: March 2011

ABSTRACTThin films of highly transparent amorphous silicon oxynitride (a-SiOx Ny:H) were prepared by rf glow discharge decomposition of SiH4,NH3 and N2O gases, in a PECVD reactor provided with an in situ phase-modulated ellipsometer. The ratio [N2O]/ ([N2O] + [NH3]) was varied from 0 to 1 in a dilution with 5% of SiH4, keeping constant the total gas flow rate. From spectroscopic ellipsometric measurements, performed in the range 1.5–5.0 eV, the refractive index of the films was calculated applying the Bruggeman effective medium theory. The structural model used considers a three-component mixture layer, composed of void, silicon dioxide (glass) and silicon nitride (pyrolitic), on a c-Si substrate. The x and y composition parameters were calculated from the fitted relative volume fraction of each constituent, ranging from a-SiO2 N0:H to a-SiO0N1.33:H, which are in fair agreement with those obtained from XPS measurements. These results, along with data of FTIR spectra of the films show a clear correlation between the void fraction and the bonded hydrogen content of the films.
Comparison of the Density and Distribution of Traps Generated by High Voltage Stress in Silicon Oxide and Silicon Oxynitrides
Authors: Richardson J. T. , Dumin D. J. , Lo G. Q. , Kwong D. L. , Gross B. J. , Sodini C. G. 
Published: March 2011

ABSTRACTA technique has been developed to determine the density and distribution of spatially deep traps throughout an insulator. These traps were created and charged by a high voltage stressing pulse and allowed to discharge upon the removal of the pulse. During the transient following pulse removal, the currents were measured. A correlation from current to trap densities and from time of decay to location within the dielectric has been made. This method has been applied to gauge the differences between nitrided dielectrics and thermal oxides. We have found initial trap levels, before stressing, to be lower in silicon oxide devices than silicon oxynitride devices. However, trap levels increased faster in thermal oxides as the stress increased, and became larger than the levels found in nitrided oxides. Nitrided devices tended to resist additional trap formation. Current-voltage measurements have shown that nitrides developed higher leakage currents as the stress was increased than did thermal oxides.
A Thermodynamic Model for the Hydrogen Incorporation in PECVD Silicon Oxynitrides Thin Layers
Authors: Cros Y. , Viscaïno S. , Arnold Bik W. M. , Habraken F. H. P. M. 
Published: March 2011

ABSTRACTIn the PECVD SixNyHzOw the hydrogen is principally incorporated as N-H bonds. For O/(O+N) below 0.4, the %H is constant at 25%; from 0.4 to 1, it decreases to 4%. We show that a chemical ordered model is likely to describe the hydrogen incorporation in the amorphous network while a random bond model fails.
Instability in Amorphous Silicon Dioxide/Amorphous Silicon Structures
Authors: Fortunato G. , Mariucci L. 
Published: March 2011

ABSTRACTAmorphous insulator/amorphous silicon structures show, under bias-stress conditions, a drift of the electrical characteristics. In the present work, in order to discriminate the main source of instability in amorphous silicon dioxide/amorphous silicon Thin-Film Transistors, the determination of both threshold voltage and flat-band voltage has been performed after bias-stressing the devices with different gate voltages and at different temperatures. Flat-band voltage was determined by the space-charge photomodulation technique. From the close correlation observed between the two quantities, we conclude that the predominant instability mechanism is represented by change in the gate insulator charge at and near the insulator/semiconductor interface. Time evolution of the threshold voltage shifts has been investigated as a function of stress bias and temperature. The data are explained in terms of a new model based on the dispersive charge injection (hopping of electrons via localised states) into the first 2–3 nm of the gate insulator adjacent to die semiconductor layer (transitional region). Possible origin of the transitional region can be related to the reduction of the gate insulator induced by activated hydrogen, as suggested by photoemission experiments performed with synchrotron radiation on SiO2 bombarded with low energy (100 eV) H-ions.
FT-IR, Sims and Electrical Characterization of Si3N4 Thin Films Obtained from C.V.D. Assisted by In-Situ Electrical Discharge
Authors: Balland B. , Bureau J. C. , Plossu C. , Botton R. 
Published: March 2011

ABSTRACTAn original process has been developed enabling the fabrication of CVD insulating (Si3N4) thin films, by means of an in-situ activation of the reactions at T < 400°C and under P=1 to 2 torr. Mono-Si substrates were nitrided using a mixture of argon containing SiH4 and NH3·O2 has also been added to the reaction gases. The activation was performed by a DC electrical discharge. The substrate was not used as an electrode and was placed parallel to the discharge current. This configuration minimized the contamination of the films during their formation. The obtained layers have been analyzed using FT-IR and SIMS.M.I.S. structures have been realized, and the flat-band shift ΔVFB and the interface state density Nit have been extracted from the high and low frequency C-V characteristics. The values of the flat-band shift depend on the discharge domain and decrease with temperature. Good electrical characteristics are obtained for thin films formed at low temperature.
In Situ Investigation of Amorphous Silicon / Silicon Nitride Interfaces by Infrared Ellipsometry
Authors: Shirai H. , Drévillon B. , Ossikovski R. 
Published: March 2011

ABSTRACTA detailed in situ study, by Infrared Phase Modulated Ellipsometry (IRPME), of interfaces between amorphous silicon (a-Si:H) and silicon nitride (a-SiNx) is presented. A behaviour compatible with a sharp interface is observed when a-SiNx is deposited on top of a-Si:H, the underlayer material being very weakly influenced by the deposition of the overlayer. In contrast a graded transition is observed when a-SiNx is deposited first. In the latter case, the IR measurements directly reveal a nitrogen incorporation in the first monolayers of a-Si:H together with an increase of intensity of the SiH bonds at the interface.
Fluorinated Gate Oxide Films Utilized in Polysilicon Thin Film Transistors
Authors: Kouvatsos Dimitrios N. , Kung Ji-Ho , Hatalis Miltiadis K. , Jaccodine Ralph J. 
Published: March 2011

ABSTRACTSilicon dioxide films have been grown on polysilicon films at low temperatures in dry ambients by utilizing NF3 - enhanced oxidation, which affords markedly enhanced oxidation kinetics. This facilitates thin film transistor applications, for which low thermal budget processing is essential. The grown oxide films are thicker than corresponding oxides grown on (100) single crystal silicon. Thin film transistors having a polysilicon self-aligned gate structure were fabricated on polycrystalline silicon. The gate oxide films were thermally grown by NF3 -enhanced oxidation at 650°C or 800°C. Electrical characterization of the TFTs having 800°C gate oxides showed on/off current ratios up to 5×107, effective electron mobilities (μneff) of 26 to 38 cm2/Vsec, threshold voltage (VT) values of 0±0.7 V and subthreshold swing (S) values as low as 0.3 V/dec. The devices were stable under dc electrical stressing at a field of 3 MV/cm. Further, the source to drain current activation energy was determined as a function of the gate voltage. The 650°C gate oxide TFTs exhibited on/off current ratio of 105, VT of 3.5 V, Uneffof10 cm2/V.sec and S of 0.7 V/dec.
Properties of Oxide-Nitride-Oxide Stacked Films for Gate Insulation in Active Matrix Displays
Authors: Waechter D. , Billard T. , Gogna P. 
Published: March 2011

ABSTRACTOxide-nitride-oxide (ONO) stacked films deposited by plasma enhanced chemical vapor deposition (PECVD) have been studied for use as the gate dielectric in active matrix displays. Good electrical properties were obtained for cadmium selenide thin film transistors (TFTs) with either ONO or single layer SiO2 gate insulation. However, the dielectric strength was up to twice as large for the ONO films. This improvement was observed with both Al and Cr electrodes.The individual oxide layers had compressive stress, while the individual nitride layers had tensile stress. When combined in an ONO structure, a net tensile stress of relatively low magnitude was obtained. Index of refraction and infrared absorption measurements indicated that the oxide films were oxygen deficient. Hydrogen incorporation was present for both the oxide and nitride films.
Amorphous Sol-Gel Insulating Films
Authors: Brinker C. Jeffrey , Warren William L. , Logan Monica N. , Ashley Carol S. 
Published: March 2011

ABSTRACTThe porosity of sol-gel thin films may be tailored for specific applications through control of the size and structure of inorganic polymers within the coating sol, the extent of polymer reaction and interpenetration during film formation, and the magnitude of the capillary pressure exerted during the final stage of drying. By maximizing the capillary pressure and avoiding excessive condensation, dense insulating films may be prepared as passivation layers on silicon substrates. Such films can exhibit excellent dielectric integrity, viz., low interface trap densities and insulating properties approaching those of thermally grown SiO2. Alternatively, through exploitation of the scaling relationship of mass and density of fractal objects, silica films can be prepared that show a variation in porosity (7–29 %) and refractive index (1.42 ndash;1.31) desired for applications in sensors, membranes, and photonics.
Electron Holographic Characterization of Ferroelectric Thin Films
Authors: Zhang Xiao , Joy David C. 
Published: March 2011

ABSTRACTIn this paper we will present recent experimental results, using electron holography and electron interferometry, of studies of ferroelectric domain walls in BaTiO3 thin films. Unlike conventional TEM diffraction contrast imaging of ferroelectrics, the new technique that we have developed not only allows direct visualization of ferroelectric domain walls and electrostatic field distributions in the vicinity of the domain wall, but also enables quantitative measurement of domain wall width and local polarization. We have measured 90° domain wall width to be between 20 to 50 Å for a BaTiO3 thin specimen. The variation of polarization across the domain wall will be shown to be close to that predicted by the Zhirnov model. The value of the measured spontaneous polarization is about 1.5×10−5 C/cm2, which is closed to the bulk macroscopically measured value.
Influence of Surface Preparation Prior to Thermal Nitridation on the Electrical Characteristics of Silicon Nitride Films Deposited on Polycrystalline Silicon Films
Authors: Mathews Viju K. , Thakur Randhir P.S. , Ditali Akram , Fazan Pierre C. 
Published: March 2011

ABSTRACTRapid thermal nitridation of the polycrystalline silicon film prior to the deposition of the silicon nitride dielectric film has been shown to be very effective in improving the dielectric characteristics for thin films. The changes at the polysilicon-silicon nitride interface has been further investigated using an in-situ clean process. This pre-treatment reduces the oxygen levels at the interface and improves the time dependent dielectric breakdown. The leakage current increases slightly due to the thinning of the silicon dioxide film at the interface.
Electrical Properties and Film Structures of (BaxSr1−x)TiO3 Thin Films by RF Sputtering
Authors: Makita T. , Horikawa T. , Kuroki H. , Kataoka M. , Tanimura J. , Mikami N. , Sato K. , Nunoshita M. 
Published: March 2011

ABSTRACTThin films of (BaxSrj-x)TiO3 (BST) deposited by RF sputtering have been studied for the application to the capacitor material of dynamic random access memory (DRAM). The effects of film structures on the dielectric constant and the leakage current were investigated. The films deposited at 550–600°C consist of granular grains, and the films deposited above 650°C contain columnar grains. The dielectric constant is related to the grain size in the direction of thickness. The leakage current increases as the film structure changes from granular to columnar. The low leakage current (less than 10−8 A/cm2 at +2 and -2 V) and the small value of equivalent SiO2 thickness (0.9 nm) were attained in the (Ba065Sr035) TiO3 thin films.
Properties of Buried SiO2 Films in Simox Structures
Authors: Revesz A. G. , Brown G. A. , Hughes H. L. 
Published: March 2011

ABSTRACTImplantation of 1.8×1018O+/cm2 into silicon results in a buried oxide (BOX) layer, nominally 400 nm thick. The as-implanted BOX has ∼1020 cm−3 dangling bonds, ∼1020cm−3 reactive sites for interaction with H (D); the dielectric properties are ill-defined, and, similarly to densified or ion-bombarded silica glass, the SiO2 network contains an increased proportion of high energy Si-O bonds, i.e. it is “strained”. After annealing above 1300°C the properties approach those of thermally grown SiO2, the dangling Si bonds are eliminated, the D-uptake decreases, the Si/SiO2 interfaces become sharper, and the dispersed silicon agglomerates into clusters of various kind. However, the properties of BOX are still significantly different from those of thermally grown SiO2 films as shown by pronounced electron trapping, large concentration of different hole traps, decreased etch rate in HF, increased D-uptake and E' center generation rate, as well as by increased bulk conduction and the presence of localized conducting defects. These phenomena are likely to be related to some oxygen deficiency, e.g. O3SiO3 groups, as oxygen treatments reduce, but not completely eliminate, the difference between BOX and thermal oxide.