bluuebunny/crossref_metadata_2025_split huggingface dataset:
Structural and optical properties of delafossite-type CuAlO2 thin films prepared by RF reactive sputtering
Authors: Yang B. , Lu Y. M. , Neumann C. , Polity A. , Wang C. Z. , Meyer B. K. 
Published: April 2011

AbstractDelafossite-type CuAlO2 thin films have been deposited by radio frequency (RF) reactive sputtering on sapphire using a CuAlO2 ceramic target. A study of structural and optical properties was performed on films of varying deposition parameters such as substrate temperature and oxygen partial pressure and also post annealing. The crystalline phase in the films was identified to be the delafossite structure by x-ray diffraction. The optical properties, such as the wavelength dependence of the transmittance and the band gap, were determined. The average transmittance is 80% in the wavelength range of 400-1500 nm and the band gap is 3.81 eV.
Sol-gel synthesis of neodymium-barium manganites utilizing microwave irradiation
Authors: Chekanova Anastasiya Evgenievna , Vanetsev Alexander Sergeevitch , Eremina Elena Alimovna , Tretyakov Yurii Dmitrievitch 
Published: April 2011

AbstractCombination of sol-gel technique and microwave treatment is effectively used for the synthesis of neodymium-barium manganite phase with improved microstructure and good magnetic properties.
In-situ TEM studies of magnetization reversal processes in magnetic nanostructures
Authors: Petford-Long Amanda K , Bromwich Thomas , Kohn Amit , Jackson Victoria , Kasama Takeshi , Dunin-Borkowski Rafal , Ross Caroline A 
Published: April 2011

AbstractOne of the most widely studied types of magnetic nanostructure is that used in devices based on the giant magnetoresistance (GMR) or tunnel magnetoresistance (TMR) phenomena. In order to understand the behaviour of these materials it is important to be able to follow their magnetisation reversal mechanism, and one of the techniques enabling micromagnetic studies at the sub-micron scale is transmission electron microscopy. Two techniques can be used: Lorentz transmission electron microscopy and off-axis electron holography, both of which allow the magnetic domain structure of a ferromagnetic material to be investigated dynamically in real-time with a resolution of a few nanometres. These techniques have been used in combination with in situ magnetizing experiments, to carry out qualitative and quantitative studies of magnetization reversal in a range of materials including spin-tunnel junctions, patterned thin film elements and magnetic antidot arrays. Quantitative analysis of the Lorentz TEM data has been carried out using the transport of intensity equation (TIE) approach.
In Situ TEM Investigation of Abnormal Grain Growth in Nanocrystalline Nickel
Authors: Follstaedt David M. , Hattar Khalid , Knapp James A. , Robertson Ian M. 
Published: April 2011

AbstractIn situ transmission electron microscopy was used to show that nanocrystalline nickel produced by pulsed-laser deposition undergoes abnormal grain growth at moderate temperatures (225-400°C). The growth rate was found to increase with thickness for the three film thicknesses examined, 50, 80 and 150 nm. The abnormal growth proceeded in an irregular manner: initiation sites and growth direction were unpredictable, and the grains exhibited no preferred orientation. Some abnormal grains show internal boundaries such as twins, while others exhibited lattice misalignments across the grain body. The grains contain many defects, including dislocations, stacking faults and surprisingly, stacking fault tetrahedra. The stacking fault tetrahedra are not a result of quenching nor of electron irradiation-induced lattice displacements; they instead are thought to form from vacancies trapped in the growing grain as it incorporates lower-density material at the high-angle grain boundaries in the nanocrystalline matrix.
Crystallographic Orientation Control of NanoCrystals Formed by FIB under a Bending Strain
Authors: Kubota Masaki , Halford Timothy Paul , Higo Yakichi 
Published: April 2011

AbstractThe application of nanocrystalline material for data-storage applications requires control over the in-plane and out –of-plane NanoCrystal (NC) orientation. In order to attempt to control the out-of-plane orientation of NCs introduced by the irradiation of Ni-P material with Ga+ ions, this processing has been completed upon material under tensile and compressive strains. The orientations of NCs nucleated have been compared to those introduced into the same material without the application of an external strain. Samples introduced under no external strain have previously been shown to be oriented with <111> parallel to the irradiated plane normal and <110> parallel to the irradiation direction. In this work, NCs nucleated under tensile strains in excess of ≈2 × 10-3 have been oriented with <112> parallel to the irradiated plane normal and <111> parallel to the applied stress direction, although <110> is still parallel to the irradiation direction. NCs formed under tensile strains lower than this critical value, as well as those formed under the compressive strain values tested, have been formed in the same orientation as those formed without the application of an external strain.
Reaction Mechanism for Deposition of Silicon Nitride by Hot-Wire CVD with Ultra High Deposition Rate(>7 nm/s)
Authors: Verlaan Vasco , Houweling Zomer Silvester , Werf Karine van der , Goldbach Hanno D , Schropp Ruud 
Published: April 2011

AbstractThe deposition process of silicon nitride (SiNx) by hot-wire chemical vapor deposition (HW CVD) is investigated by exploring the effects of process pressure and gas-flow ratio on the composition of the deposited SiNx films. Furthermore, experiments with D2 and deuterated silane were performed to gain further insight in the deposition reactions taking place. It appeared that the N/Si ratio in the layers determines the structural properties of the deposited films and since the volume concentration of Si-atoms in the deposited films is constant with N/Si ratio, the structure of the films are largely determined by the quantity of incorporated nitrogen. Because the decomposition rate of the ammonia source gas is much smaller than that of silane, the properties of the SiNx layers are largely determined by the ability to decompose the ammonia and to incorporate nitrogen into the growing material. It appeared that the process pressure greatly enhances the efficiency of the ammonia decomposition, presumably caused by the higher partial pressure of atomic hydrogen. With this knowledge we increased the deposition rate to a very high value of 7 nm/s for dense transparent SiNx films, much faster than conventional deposition techniques for SiNx can offer. Despite this high deposition rate good control over the composition is achieved by varying the flow ratio of the source gasses. Depositions performed with deuterated silane as a source gas reveal that almost all hydrogen in N-rich films originates from ammonia, probably caused by SiNx matrix formation by cross linking reactions
Dual-Chamber Plasma Co-Deposition of Nanoparticles in Amorphous Silicon Thin Films
Authors: Anderson C. , Blackwell C. , Deneen J. , Carter C. B. , Kakalios James , Kortshagen U. 
Published: April 2011

AbstractThe production of hydrogenated amorphous silicon films containing silicon nanocrystal-line inclusions (a/nc-Si:H) is demonstrated using a new deposition process. Crystalline Si nanoparticles around 5 nm in diameter are generated in a flow-through plasma reactor, and are introduced into a downstream capacitively-coupled plasma enhanced chemical vapor deposition reactor where the particles are “co-deposited” with the amorphous phase of the film. Transmis-sion electron microscopy confirms the presence of crystalline inclusions in these films, as well as providing confirmation that the crystalline particles are indeed produced in the flow-through re-actor and not in the capacitive plasma. Electrical measurements indicate an improvement in the dark conductivity of the intrinsic a/nc-Si:H films as the particle concentration is increased, sug-gesting that the particles have a doping effect on the films charge transport properties.
Orientation-Dependent Dewetting of Patterned Thin Si Film on SiO2
Authors: Dornel Erwan , Barbé J-C. , Eymery J. , Crécy F. de 
Published: April 2011

AbstractThe agglomeration of a Silicon On Insulator (001) film during a thermal annealing at 900°C and 950°C under hydrogenated atmosphere has been characterized by Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). At this temperature, the Si faceting along {110}, {111} and {113} planes is interpreted by a surface energy anisotropy. The anisotropy of the diffusion coefficient is also revealed by the formation of Si line along the <510>, <110> and <100> directions. A mechanism of the pearling instability of the <510> lines is proposed.
Photocarrier Radiometric Lifetime Measurements of Intrinsic Amorphous-Crystalline Silicon Heterostructure
Authors: Leong Keith R , Mandelis Andreas , Kherani Nazir P , Zukotynski Stefan 
Published: April 2011

AbstractIntrinsic hydrogenated amorphous silicon films were deposited by the DC saddle field system on crystalline silicon wafers. The substrate temperature of the amorphous film, crystalline silicon surface cleaning schemes, and the native oxide etchant were varied. The transport parameters of the amorphous-crystalline silicon heterostructures were evaluated by Photocarrier Radiometric (PCR) lifetime measurements. PCR bulk lifetime estimates were obtained using the quinhydrone in methanol solution to passivate the crystalline silicon surface. We present the effectiveness of the PCR system in evaluating different surface passivation schemes.
Combination of Metal Nano-Imprint and Excimer Laser Annealing for Location Control of Si Thin-Film Grain
Authors: Nakagawa Gou , Asano Tanemasa 
Published: April 2011

AbstractA novel method of locating Si thin-film grains by combining metal nano-imprint and excimer laser annealing (ELA) is demonstrated. Metal nano-imprint at the a-Si film surface is used for the purpose of creating Si crystal nuclei which act as the seed for the subsequent crystallization by using ELA. The annealing to form nuclei at imprinted sites was carried out at temperatures below 450oC. ELA using XeCl laser of the sample with capping SiOx film resulted in the formation of over 2.0 μm-sized Si crystal grains at controlled position. Electron back-scattering pattern (EBSP) analysis showed that about 75% of the boundaries inside the location-controlled grains were the coincidence site lattice boundaries.
Correlation Between Annealing Temperature and Crystallinity of Si Films Prepared by Thermal Plasma Jet Crystallization Technique
Authors: Kaku Hirotaka , Higashi Seiichiro , Okada Tatsuya , Murakami Hideki , Miyazaki Seiichi 
Published: April 2011

AbstractTransient reflectivity of amorphous Si (a-Si) films during thermal plasma jet (TPJ) irradiation has been measured to characterize the phase transformation in millisecond time domain. The a-Si films first transform to crystalline by solid phase crystallization (SPC) followed by melting of the film, and then solidifies to the final crystalline state. By increasing the SPC temperature from about 1100 K to 1300 K, the duration of phase transformation decreases from about 1 ms to 100 μs. The crystallinity of the SPC films is improved not only by annealing the films at a high temperature but also annealing them with longer duration.
Bias Stress Stability of Asymmetric Source-Drain a-Si:H Thin Film Transistors
Authors: Shin Kwang-Sub , Lee Jae-Hoon , Lee Won-kyu , Park Sang-Geun , Han Min-Koo 
Published: April 2011

AbstractThe threshold voltage (VT) degradation of asymmetric source-drain a-Si:H TFTs due to the electrical stress has been investigated. In the absence of a drain bias (VG=15V, VD=0V), the threshold voltage (VT) shifts of asymmetric TFTs were similar to that of symmetric TFT. However, in the presence of drain bias (VG=15V, VD=20V), the VT shifts of asymmetric TFTs were less than symmetric TFT. The VT shifts of ‘L’ and ‘J’ shaped TFT were 0.29V, 0.24V respectively, while the VT shift of ‘I’ shaped TFT was 0.42V.The less VT degradation of the asymmetric source-drain a-Si:H TFT compared with the symmetric TFT may be explained by the defect creation model. Since the actual drain width of asymmetric TFT is longer than symmetric TFT at the same W/L ratio, the charge depletion due to the drain bias is larger than that of the asymmetric TFT. Due to the less carrier concentration in the channel, the asymmetric a-Si:H TFT shows the less VT degradation compared with the symmetric TFT.
Nanocrystalline Silicon Films Deposited by RF PECVD for Bottom-gate Thin-film Transistors
Authors: Esmaeili Rad Mohammad Reza , Lee Czang-Ho , Sazonov Andrei , Nathan Arokia 
Published: April 2011

AbstractThin-film transistors (TFTs) in active-matrix organic light emitting diode (AMOLED) displays are required to supply high and stable driving current to OLEDs. Top-gate TFTs with nanocrystalline silicon (nc-Si) active layer have shown promise to render high mobility and stable driving current. However, to be compatible with current production facilities, bottom-gate TFTs are demanded. Currently, bottom-gate nc-Si TFTs show insufficient field effect mobility and exhibit driving current instability due to presence of amorphous incubation layer at the interface with gate dielectric. Our research is motivated by the need to eliminate the incubation layer. In order to do so, we studied nc-Si deposition process to find the RF PECVD deposition regimes which lead to minimum incubation layer.We have deposited a set of undoped nc-Si films by 13.56 MHz PECVD at 250°C by varying RF power, reactor pressure, silane and hydrogen flow rates. Raman spectroscopy, constant-photocurrent method (CPM) and optical absorption have been used to measure film crystallinity, defect density and optical bandgap, respectively. Carrier transport in the films has been studied using dark conductivity, photoconductivity and conductivity activation energy measurements.Our results reveal that silane and hydrogen flow rates are the most contributing factors to film characteristics. The results also indicate that the reactor pressure does not have a significant effect on the film crystallinity. However, CPM data confirm that to obtain lower defect density, medium or high deposition pressures are preferred. We obtained films with dark conductivity and Raman crystallinity in the order of 10-6-10-7S/cm and 60-80 %, respectively. Furthermore, we have deposited nc-Si films as thin as 20nm with 60% crystallinity, which is crucial for bottom-gate TFTs. Finally, four different sets of bottom-gate TFTs have been fabricated by changing gate dielectric compositions and changing [SiH4]/([SiH4] + [H2]) gas flow ratio. The device performance, relationship to the film structure and deposition process, and future improvements will be discussed in details.
Channel Cracking Technique For Toughness Measurement Of Sioch Low-K Films
Authors: Brillet-Rouxel Helene , Dupeux Michel , Braccini Muriel , Orain Stéphane 
Published: April 2011

AbstractThe technique of channel cracking is used to study the crack growth in SiOCH low-k films. Various film thicknesses are produced using consecutive PECVD deposits on silicon substrates in up to the critical thickness for which spontaneous cracks appear. After determining mechanical properties and residual stresses of these films, samples are cleaved, and subjected to four-point bending tests. During the loading in ambient environment, cracks propagate from defects due to cleavage. Propagation of these cracks is observed in situ in order to correlate crack growth velocities to film thickness and total stress in the film. These results allow plotting crack growth rate versus stress intensity factor for crack velocity varying from 10-9 to 10-4 m/s for a stress intensity factor about 0.1 MPa√m. Moreover, in this range of velocities a model is proposed for this material to determine the film stress required to produce channel cracking, for a given film thickness.
Aqueous Based Single Wafer Cleaning Process Development and Integration into 65nm Process Flow using Metal Hard Mask
Authors: Lin Miao-Chun , Wang Mei-Qi , Weng Cheng-Ming , Chou Chopin , Liao JH , Tang Jianshe , Weng Willey , Lu Wei , Chen Han-Wen , Lee John TC 
Published: April 2011

AbstractAs the industry develops processes for the 65 and 45 nm technology nodes, post etch/ash cleaning faces new challenges with far more stringent requirements on surface cleanliness and materials loss. The introduction and integration of new materials, such as metal hard mask, creates additional requirements for wafer cleaning due to the occurrence of new defect modes related to metal hard mask. These include organometallic residue and metal fluorite compounds precipitating with time. We have developed a novel aqueous solution (AQ) based single wafer cleaning process to address these new defect modes. Physical characterization results and process integration electrical data and reliability data (TEM cross section review of the vias) are presented in this paper.The main conclusions can be summarized as follows: (1) In the dual damascene Cu/low-k process flow with hard mask, there are three typical residues after etch/ash: generic polymer residue, organometallic residue strongly bonded to metal maks, and time-dependent metal fluoride residue. (2) Generic polymer residue is very well characterized [1,2] and is usually easy to remove with solvent or aqueous solution [2,3]. (3)We developed an oxidizing chemistry based process to undercut the hard mask for the organometallic residue removal, which proved highly effective. (4)The time-dependent metal fluoride reside makes queue time control after etch/ash very critical (<1 hour). We developed a process with a fluorine based aqueous chemistry to address the metal fluoride residue, which proved highly effective. With this new process, queue time control is not required. (5) The post etch/ash cleaning for the Cu/low-k structure with metal hard mask typically employs the solvent/dry plasma ash multi-step procedure [4]. The new process developed in this research reduced the multi-step process to one wet clean step with two different aqueous chemistries in sequence. (6) The integration electrical data shows that the new single step aqueous cleaning process performance is comparable to, or even better than that from the solvent/dry plasma ash multi cleaning process. (7) Blanket Cu loss with the new process is about 23A/min, however TEM analysis of the vias after full integration shows Cu loss, we are working to improve the integration related Cu loss.
Epitaxial GaN Layer Growth Using Nitrogen Enriched TiN Buffer Layers
Authors: Ito Kazuhiro , Uchida Yu , Lee Sang-jin , Tsukimoto Susumu , Ikemoto Yuhei , Hirata Koji , Shibata Naoki , Murakami Masanori 
Published: April 2011

AbstractAbout 20 years ago, the discovery of an AlN buffer layer lead to the breakthrough in epitaxial growth of GaN layers with mirror-like surface, using a metal organic chemical vapor deposition (MOCVD) technique on sapphire substrates. Since then, extensive efforts have been continued to develop a conductive buffer layer/substrate for MOCVD-grown GaN layers to improve light emission of GaN light-emitting diodes. In the present study, we produced MOCVD-grown, continuous, flat epitaxial GaN layers on nitrogen enriched TiN buffer layers with the upper limit of the nitrogen content of TiN deposited at room temperature (RT) on sapphire substrates. It was concluded that the nitrogen enrichment would reduce significantly the TiN/GaN interfacial energy. The RT deposition of the TiN buffer layers suppresses their grain growth during the nitrogen enrichment and the grain size refining must increase nucleation site of GaN. In addition, threading dislocation density in the GaN layers grown on TiN was much lower than that in the GaN layers grown on AlN.
Investigation of NBTI Recovery During Measurement
Authors: Entner Robert , Grasser Tibor , Enichlmair Hubert , Minixhofer Rainer 
Published: April 2011

AbstractIn this work we present a rigorous investigation of the negative bias temperature instability (NBTI) recovery process during measurement intervals in comparison to the numerical solution of an extended reaction-diffusion (RD) model. In contrast to previous work, the RD model has been implemented in a multi-dimensional device simulator and is solved self-consistently together with the semiconductor device equations. This allows us to directly use many commonly approximated quantities such as the oxide electric field and the interface hole concentration in a self-consistent manner. In addition, the influence of the trapped charges can be more accurately considered by using a distributed Shockley-Read-Hall interface trap-charge model which has been coupled to the RD model. Thus, due to the self-consistent solution procedure, also the feedback of these charged interface-states on the Poisson equation is considered which influences the observed threshold voltage shift. Experimental data confirm the model which has been calibrated to a wide range of temperatures using a single set of parameters.
Enhanced Phonon-Energy Coupling: Dramatic Reduction of Leakage Current of Silicon Oxide
Authors: Chen Zhi , Guo Jun , Samantaray Chandan B 
Published: April 2011

AbstractWe study in detail a newly discovered effect, phonon-energy-coupling enhancement (PECE) effect, produced by rapid thermal processing (RTP). It includes two aspects: (1) Strengthening Si-D bonds and Si-O bonds and (2) Change of energy band structure and effective mass due to thermal shock. It is shown that not only Si-D bonds but also Si-O bonds have been strengthened dramatically, leading to enhancement of robustness of the oxide structure and the oxide/Si interface. For thick oxides (>3 nm), the gate leakage current has been reduced by two orders of magnitude and the breakdown voltage has been improved by ~30% due to phonon-energy coupling. For ultrathin oxides (2.2 nm), the direct tunneling current has been reduced by five-orders of magnitude, equivalent to that of HfO2, probably due to the increased effective mass and barrier height.
Atomistic Analysis of Crystal Plasticity in Copper Nanowire
Authors: McEntire R. S. , Shen Y.-L. 
Published: April 2011

ABSTRACTPlastic deformation in a model copper wire under tensile loading is modeled using three dimensional atomistic simulations. The primary objective is to gain fundamental insight into the nano-scale deformation features. An initial defect is utilized in the model to trigger plastic deformation in a controlled manner. A parametric study is performed by varying the atomic interaction range used in the model. When the interaction distance is small, dislocation slip is observed to be the dominant deformation mechanism. A slight increase in the interaction range results in phase transition from the FCC structure to a BCC structure. Re-orientation of the BCC lattice also occurs at later stages of the deformation. The phase transition mechanism is further enhanced if the nanowire is attached to a flat substrate.
Investigation of the Influence of Grain Size, Texture and Orientation on the Mechanical behavior of Freestanding Polycrystalline Gold Films
Authors: Wang Liwei , Prorok Bart 
Published: April 2011

ABSTRACTPolycrystalline gold thin films with thickness of 250nm, 500nm and 1000nm were deposited on Si substrates by means of both E-Beam evaporation and sputtering techniques. High-resolution SEM, including electron-backscattered diffraction (EBSD), was employed to provide a crystallographic analysis including grain orientation maps of the studied films. The Membrane Deflection Experiment (MDE) was employed to perform the microscale tensile testing. The Young's modulus of gold films deposited by E-Beam evaporation was measured consistently in the range of 55-62 GPa while it increased to 68-72 GPa for sputtered films. Plastic yielding of the e-beam and sputtered films was contrasted due to varying microstructure of each deposition technique, which appears to assert a measure of control on the deformation mechanics.