bluuebunny/crossref_metadata_2025_split huggingface dataset:
Structural Analyses and Magnetic Properties of Multiple-Structure Multilayered Co/Au Films
Authors: Koiwai Rimika , Kobayashi Masanobu , Maeno Yoshinori 
Published: June 2019

AbstractIn the interfaces of multilayered Co/Au and Co/Pd films, there were some interesting changes with annealing. For profile fittings, which is a comparison between measured peaks of X-ray diffraction and calculated peaks of the extended 3-step model profile fittings, the mixed layers between Co layers and noble metal layers were decreased in Co/Au films while increased in Co/Pd films. These results are based on the difference that Co-Au is a eutectic system while Co-Pd is an isomorphous system. This time, as new research, we fabricated multiple-structure multilayered Co/Au films (MSM Co/Au films). Magnetic properties and structural analyses were carried out with a vibrating sample magnetometer (VSM), X-ray diffraction (XRD), and extended 3-step model profile fittings. MSM Co/Au films have two periodic thicknesses. MSM Co/Au films showed the same perpendicular magnetization as Co/Au and Co/Pd films, which is dependent on the Co layer thickness. Perpendicular magnetization showed the maximum value after 1 h-annealing at 473 K. It was well confirmed that the mixed layers decreased at this annealing condition with the extended 3-step model profile fittings.
Evaluation of the Chemical-mechanical Planarization (CMP) Performance of Silicon Nitride and Silicon Carbide as Hard Mask Materials for Cu-based Interconnect Technology
Authors: Tseng Wei-Tsu , Lee Jia , Das Sanjit , Fitzsimmons John , Biery Glenn , Barth Edward , Goldblatt Ronald 
Published: June 2019

AbstractHydrogenated silicon nitride, hydrogenated silicon carbide, and their intermediates were chemo-mechanically polished. Results showed that, within the material set examined, harder materials also have higher CMP removal rates. In addition, CMP rates for multilayer stacks did not follow those for single layers. Polish mechanisms were proposed to explain these phenomena.
Engineering the Interaction Forces to Optimize CMP Performance
Authors: Basim G. B. , Vakarelski I. , Singh P. , Moudgil B. M. 
Published: June 2019

AbstractThe main objective of Chemical Mechanical Polishing (CMP) process is to planarize the metal or dielectric layers deposited on the wafer surfaces in microelectronics device manufacturing. In CMP, slurries containing submicrometer size particles and chemicals are used to achieve planarization. An effective polishing requires an optimal material removal rate with minimal surface deformation. Therefore, it is important to control the particle-substrate interactions that are responsible for the material removal and the particle-particle interactions, which control the slurry stability and consequently the defect density. This paper discusses the impact of interaction forces on polishing, and underlines the scientific guidelines to formulate consistently high performing CMP slurries.
Material Structure of Microcrystalline Silicon Deposited with an Expanding Thermal Plasma
Authors: Smit C. , Williamson D.L. , Sanden M.C.M. van de , Swaaij R.A.C.M.M. van 
Published: June 2019

AbstractExpanding thermal plasma CVD (ETP CVD) has been used to deposit thin microcrystalline silicon films. In this study we varied the position at which the silane is injected in the expanding hydrogen plasma: relatively far from the substrate and close to the plasma source, giving a long interaction time of the plasma with the silane, and close to the substrate, resulting in a short interaction time. The material structure is studied extensively. The crystalline fractions as obtained from Raman spectroscopy as well as from X-ray diffraction (XRD) vary from 0 to 67%. The average particle sizes vary from 6 to 17 nm as estimated from the (111) XRD peak using the Scherrer formula. Small angle X-ray scattering (SAXS) and flotation density measurements indicate void volume fractions of about 4 to 6%. When the samples are tilted the SAXS signal is lower than for the untilted case, indicating elongated objects parallel to the growth direction in the films. We show that the material properties are influenced by the position of silane injection in the reactor, indicating a change in the plasma chemistry.
Prediction of the Interface Response Functions for Amorphous and Crystalline Phases of Silicon and Germanium
Authors: Albenze Erik J. , Matejik Laura A. , Fynan Nick F. , Clancy Paulette 
Published: June 2019

AbstractInterface response functions that govern the solidification kinetics of amorphous and crystalline phases of Si and Ge have been determined for reparameterized versions of the Stillinger-Weber (SW) potential. The strength of the three-body term in the SW potential and the energy scaling parameter were modified to obtain agreement with the experimental melting temperatures of both the amorphous and crystalline phases. These modified models were used to produce predictions of the interface response function for both Si and Ge that adequately fit the few known experimental data.
Size Distribution Of Embedded Nano-Crystallites In Polymorphous Silicon Studied By Raman Spectroscopy And Photoluminescence
Authors: Tripathi V. , Mohapatra Y. N. , Suendo V. , Cabarrocas P. Roca i 
Published: June 2019

AbstractPolymorphous Silicon (pm-Si:H) deposited by Plasma Enhanced Chemical Vapour Deposition (PECVD) has emerged as an alternative material to amorphous silicon (a-Si:H). Deposition parameters of pm-Si:H are such that small crystallites get embedded in a relaxed amorphous silicon matrix, thus improving the optical and electrical properties. We study the size of crystallites and degree of order in pm-Si:H using Raman and photoluminescence (PL) spectra of pm-Si:H and a-Si:H. Raman Spectra of a variety of hydrogenated nanostructured silicon (pmSi:H) and amorphous Silicon (a-Si:H) samples grown at different pressures were analyzed. Deconvolution of observed multiple peaks in photoluminescence spectra and fitting to Gaussian size distribution also yields particle size to be in the range of 2.3 to 3.5nm in agreement with Transmission Electron Microscopy and Raman results.
Low-temperature Growth of Poly-Si and SiGe Thin Films by Reactive Thermal CVD and Fabrication of High Mobility TFTs over 50 cm2/Vs
Authors: Hanna Jun-Ichi , Shimizu Kousaku 
Published: June 2019

AbstractWe have established a new thermal CVD technique, Reactive Thermal CVD, for polycrystalline silicon (poly-Si) and silicon germanium (poly-SiGe) thin films aiming at thin film transistors (TFTs) applications, in which a low substrate temperature of 450°C enables us to use glass substrates. This technique achieved high crystallinity at very early stage of the film growth, resulting no amorphous incubation layer on the substrate surface. We fabricated bottom and top gate n-and p-channel TFTs with these of 200 nm thick films on SiO2/Si wafers and glass substrates, respectively: the high field effect mobilities as high as 55 cm2/Vs and 25 cm2/Vs were achieved in the bottom-gate and top-gate TFTs, respectively. Here, we discuss the technical requirements in the low-temperature CVD technique for the large-area poly-Si thin films and how they can be achieved in the reactive thermal CVD.
Leakage Current Behavior in Common I-Layer A-SI:H P-I-N Photodiode Arrays
Authors: Theil Jeremy A. 
Published: June 2019

AbstractHydrogenated amorphous silicon photodiode arrays form the basis of monolithic three-dimensional integrated circuit sensor technology. In these arrays, the intrinsic a-Si:H layer covers the entire area to maximize light collection. One technique by which the pixel diode is defined, is to pattern the bottom contact layer independently of the intrinsic layer. One of the most important characteristics of any diode array, however, is that the dark-state reverse bias leakage currents must be as low as possible to minimize diode noise. This study examines the leakage currents associated with the pixelated array. These structures are unique in that the edge of the diode is defined by the local electric field between diodes, rather than the physical surface of an a-Si:H film. The effect of the diode edge has been found to induce a field-dependent component to the reverse bias leakage current. For example, diodes with 5500Å i-layer, have a junction leakage of 14 to 20 pA/cm2, at 5.0 x 104 V/cm, while the pixel edge-dependent current component can be as high as 30 pA/cm2. In addition, it will be shown that the i-layer thickness and junction doping plays a key role in determining the behavior of the leakage currents.
Enhanced Blue Sensitivity in ITO/a-SiNx:H/a-Si:H MIS Photodetectors
Authors: Tao S. , Vygranenko Y. , Nathan A. 
Published: June 2019

AbstractWe report an ITO/a-SiNx:H/a-Si:H MIS photodetector with improved performance in terms of its dark current, stability, and spectral response in the blue region. The a-Si:H and a-SiNx:H thin film layers were deposited by plasma-enhanced chemical vapor deposition (PECVD) on a glass substrate with patterned Mo back contact. The ITO was polycrystalline with a wide band gap (>3.75 eV) and was deposited at room temperature by magnetron sputtering. SIMS (Secondary Ion Mass Spectrometer) measurements show that an ultra thin a-SiNx:H film (a few nm) can effectively block the diffusion of oxygen from the ITO to the a-Si:H. In addition, the insulator layer provides a barrier for electrons, which serves to reduce the dark current. This is in contrast to the ITO/a-Si:H Schottky photodiode whose electrical and optical performance is impaired by the large defect density at the interface due to impurity diffusion from the ITO layer. At a reverse bias of 1 V, the dark current density of the MIS photodetector is as low as 4 nA/cm2. Photoresponse measurements show a dramatically enhanced sensitivity in the UV/blue spectral region. A high quantum efficiency (∼80%) is achieved at a wavelength of 440 nm, which can be attributed to reduction of both optical and recombination loses by virtue of the highly transparent polycrystalline ITO and the low defect density at the a-SiNx:H/a-Si:H interface.
Hydrogenated Microcrystalline Silicon Single-Junction and Multi-Junction Solar Cells
Authors: Yan Baojie , Yue Guozhen , Yang Jeffrey , Banerjee Arindam , Guha Subhendu 
Published: June 2019

AbstractThis paper summarizes our recent studies of hydrogenated microcrystalline silicon (μc-Si:H) solar cells as a potential substitute for hydrogenated silicon germanium alloy (a-SiGe:H) bottom cells in multi-junction structures. Conventional radio frequency (RF) glow discharge is used to deposit hydrogenated amorphous silicon (a-Si:H) and μc-Si:H at low rates (∼ 1 Å/s), searching for the highest efficiency. We have achieved an initial active-area efficiency of 13.0% and stable efficiency of 11.2% using an a-Si:H/μc-Si:H double-junction structure. Modified very high frequency (MVHF) glow discharge is used to deposit a-Si:H and μc-Si:H at high rates (∼ 3-10 Å/s) for comparison with our a-Si:H/a-SiGe:H/a-SiGe:H triple-junction production technology. The deposition time for the μc-Si:H intrinsic (i) layer in the bottom cell should be less than 30 minutes in order to be acceptable for mass production. To date, an initial active-area efficiency of 12.3% has been achieved with the bottom cell deposited in 50 minutes. By increasing the deposition rate and reducing the bottom cell thickness, we have achieved an initial active-area efficiency of 11.4% with the bottom cellilayer deposited in 30 minutes. The cell stabilized to 10.4% after prolonged light soaking. We will address issues related to μc-Si:H material, solar cell design, solar cell analysis, and stability.
Femtosecond Far-Infrared Studies of Carrier Dynamics in Hydrogenated Amorphous Silicon and Silicon-Germanium Alloys
Authors: Nampoothiri A. V. V. , Nelson B. P. , Dexheimer S. L. 
Published: June 2019

AbstractWe present femtosecond time-resolved studies of the photoexcited carrier response in the far-infrared spectral range in PECVD a-Si:H and a-SiGe:H thin films. The experiments are carried out using an optical pump / terahertz (THz) probe technique, in which a femtosecond pump pulse excites carriers in the sample and a time-delayed probe pulse measures the resulting change in the far-infrared optical properties as a function of time delay following the excitation. These measurements are sensitive to carrier processes at low energy, corresponding to a range of approximately 1 - 10 meV, a key energy scale in these materials. We find that the observed photoexcited carrier dynamics are consistent with trapping of carriers into band tail states on a picosecond time scale.
The Reliability of Measurements on Electron Energy Distribution Function in Silane rf Glow Discharges
Authors: Lin Kuixun , Lin Xuanying , Chi Linfei , Yu Chuying , Yu Yunpeng , Liu Shi 
Published: June 2019

AbstractElectron energy distribution function (EEDF) is directly proportional to the second derivative of the probeI-Vcharacteristics. Because of an amplifying effect of unavoidable noises in the experimental probeI-Vcurves on the derivation process, the experimentalI-Vcurves should be smoothed before performing the numerical derivation. This article investigates the effect of adjustable factors used in the smoothing process on the deduced second derivative of theI-Vcurves, and an optimum group of the adjustable factors is selected to make the rms deviation of the smoothedI-Vcurves from the measured ones less than 1 %. A simple differentiation circuit is designed and used to measure the EEDF parameter straightforwardly. It is the first time, so far as we know, to measure the EEDF parameters simultaneously by means of both numerical and circuit derivative methods under the same discharge conditions and on the same discharge equipment. The deviation between two groups of mean electron energy (E) and electron density (ne) obtained by the above different methods is within about 7 %. This apparently improves the reliability of the measurements on the EEDF parameters.
Microcrystalline (Si,Ge):H Solar Cells
Authors: Zhu Jianhua , Dalal Vikram L. 
Published: June 2019

AbstractWe report on the growth and properties of microcrystalline Si:H and (Si,Ge):H solar cells on stainless steel substrates. The solar cells were grown using a remote, low pressure ECR plasma system. In order to crystallize (Si,Ge), much higher hydrogen dilution (∼40:1) had to be used compared to the case for mc-Si:H, where a dilution of 10:1 was adequate for crystallization. The solar cell structure was of the p+nn+ type, with light entering the p+ layer. It was found that it was advantageous to use a thin a-Si:H buffer layer at the back of the cells in order to reduce shunt density and improve the performance of the cells. A graded gap buffer layer was used at the p+n interface so as to improve the open-circuit voltage and fill factor. The open circuit voltage and fill factor decreased as the Ge content increased. Quantum efficiency measurements indicated that the device was indeed microcrystalline and followed the absorption characteristics of crystalline ( Si,Ge). As the Ge content increased, quantum efficiency in the infrared increased. X-ray measurements of films indicated grain sizes of ∼ 10nm. EDAX measurements were used to measure the Ge content in the films and devices. Capacitance measurements at low frequencies ( ~100 Hz and 1 kHz) indicated that the base layer was indeed behaving as a crystalline material, with classical C(V) curves. The defect density varied between 1x1016 to 2x1017/cm3, with higher defects indicated as the Ge concentration increased.
Impact of Low k Dielectrics on Electromigration Reliability for Cu Interconnects
Authors: Ho Paul S. , Lee Ki-Don , Ogawa Ennis T. , Yoon Sean , Lu Xia 
Published: June 2019

AbstractMulti-link statistical test structures were used to study the effect of low k dielectrics on EM reliability of Cu interconnects. Experiments were performed on dual-damascene Cu interconnects integrated with oxide, CVD low k, porous MSQ, and organic polymer ILD. The EM activation energy for Cu structures was found to be between 0.8 and 1.0 eV, indicating mass transport is dominated by diffusion at the Cu/SiNx cap-layer interface, independent of ILD. Compared with oxide, the decrease in lifetime and (jL)c observed for low-k structures can be attributed to less dielectric confinement in the low k structures. An effective modulus B obtained by finite element analysis was used to account for the dielectric confinement effect on EM. For all the ILDs studied, (jL)c showed no temperature dependence.
Characterization of Electroplated Copper Films with Laser-Generated Surface Acoustic Waves
Authors: Maznev A.A. , Gostein M. , Brongersma S.H. 
Published: June 2019

AbstractElastic properties of electroplated copper films fabricated under different plating and annealing conditions have been characterized with laser-generated surface acoustic waves. For acoustic wavelengths longer than the characteristic copper grain size, the effective elastic modulus of copper was found to be unaffected by variations of the plating current as well as by the grain size variation due to different annealing temperatures. Consequently, copper thickness measurements with surface acoustic waves have been found to be more stable with respect to process variations than electrical sheet resistance measurements. For short acoustic wavelengths (∼ 2 νm), grain growth results in a significant increase of acoustic attenuation and a shift in the measured velocity. This finding opens an opportunity for copper structure monitoring by surface wave-based optoacoustic metrology.
Enhanced adhesion of Cu film on a low-k material by using Ti glue layer, B dopant and N2 plasma treatment
Authors: Ko Y.K. , Lee S. , Yang H.J. , Shim C. , Jung D. , Lee J.G. 
Published: June 2019

AbstractAdhesion property of Cu film on a low-k material was investigated. The low-k films deposited using a mixture of hexamethyldisilane(HMDS) and para-xylene had a dielectric constant as low as 2.7 and thermal stability up to 400°C. In this work, Ti glue layer, boron dopant, and N2 plasma treatment were applied to improve adhesion between Cu and the low-k films. Adhesion property was significantly enhanced by N2 plasma-treatment on the low-k film and boron dopant in Cu film. This enhanced adhesion was attributed to the formation of new binding states between Ti and the plasma-treated surface of the low-k film and to the diffusion of B from Cu to Ti and low-k films. Cu(B)/Ti/low-k film annealed at 350°C withstood an applied load of about 23 N during the scratch test.
Dual Damascene Process for FatWires in Copper/FSG Technology
Authors: Gambino J. , Stamper T. , Trombley H. , Luce S. , Allen F. , Weinstein C. , Reuter B. , Dunbar M. , Samek V. , McLaughlin P. , Kane T. 
Published: June 2019

AbstractA trench-first dual damascene process has been developed for fat wires (1.26 μm pitch, 1.1 μm thickness) in a 0.18 μm CMOS process with copper/fluorosilicate glass (FSG) interconnect technology. The process window for the patterning of vias in such deep trenches depends on the trench depth and on the line width of the trench, with the worse case being an intermediate line width (lines that are 3X the via diameter). Compared to a single damascene process, the dual damascene process has comparable yield and reliability, with lower via resistance and lower cost.
Development of porous SiLK™ Semiconductor Dielectric Resin for the 65 nm and 45 nm Nodes
Authors: Strittmatter R. J. , Hahnfeld J. L. , Silvis H. C. , Stokich T. M. , Perry J. D. , Ouellette K. B. , Niu Q. J. , Godschalx J. P. , Kalantar T. H. , Mubarekyan E. , Hefner R. E. , Lyons J. W. , Dominowski J. M. , Buske G. R. 
Published: June 2019

AbstractPorous SiLK resin is an ultra-low-k interlayer dielectric (ILD) material designed to meet the needs of the 65 nm technology node and beyond. In early 2002, the porous SiLK resin formulation was defined and scaled up, facilitating the tight monitoring and control of key properties, including pore size distribution, over several lots of material. The film processing kinetics are now well understood and a wide process window exists which ensures optimum pore morphology and pore size distribution. Thermal cycling of films demonstrates no effect on pore morphology or dielectric constant. The material has been designed to minimize the impact of CTE mismatch at high temperature, which challenged the integration of some previous generations of SiLK and porous SiLK dielectric resins. The discrete, closed-cell pore geometry is well characterized and enables the extendibility of process module development from SiLK resin technology to porous SiLK resin. Concurrent with the scale up efforts, advancements in minimizing both cure time and temperature simultaneously, as well as significant improvements in pore size and pore size distribution, have been achieved. The cure and porogen burn out time has been reduced by 50% or greater, and the temperature has been reduced to 370°C. The pore size has been reduced by ∼35%, and the pore size distribution has been narrowed by ∼40%. These advancements have resulted in the introduction of porous SiLK T resin, with a dielectric constant of k = 2.4 and a recommended cure temperature of 370°C, and the introduction of porous SiLK U resin, with a mean pore diameter of ∼5 nm and a dielectric constant of k = 2.2.
Characterization of Boron Carbo-Nitride Films Deposited By Low Temperature Chemical Vapor Deposition
Authors: Engbrecht E. R. , Cilino C. J. , Junker K. H. , Sun Y.M , White J. M. , Ekerdt J. G. 
Published: June 2019

AbstractThis study reports low temperature chemical vapor deposition of amorphous boron carbonitride films on SiO2 using a dimethylamine borane complex at temperatures ranging from 360 to 500°C and with varying NH3 flow at 360°C. The dielectric constant, k, of the films ranged from 4.11 to 4.83, and increased with temperature while the addition of nitrogen using NH3 decreased k. The index of refraction changed correspondingly with k, ranging from 1.826 to 2.226. Higher substrate temperature caused nitrogen and carbon content to increase with additional bonding to boron. The addition of ammonia increased the N:B ratio to as high as 0.64 and reduced k to 4.11. The higher nitrogen incorporation displaced both boron and carbon in the film, leaving boron bonded primarily to nitrogen and other boron atoms. These films were amorphous with smooth surfaces of RMS roughness ranging from 0.30 nm to 0.53 nm.
Spectrum of Defect States in Porous Organic Low-k Dielectric Films, Annealed in Argon and Nitrogen
Authors: Ligatchev V. , Wong T.K.S. , Goh T.K. , Suzhu Yu Rusli 
Published: June 2019

AbstractDefect spectrum N(E) of porous organic dielectric (POD) films is studied with capacitance deep-level-transient-spectroscopy (C-DLTS) in the energy range up to 0.7 eV below conduction band bottom Ec. The POD films were prepared by spin coating onto 200mm p-type (1 – 10 Δcm) single-side polished silicon substrates followed by baking at 325°C on a hot plate and curing at 425°C in furnace. The film thickness is in the 5000 – 6000 Å range. The ‘sandwich’ -type NiCr/POD/p-Si/NiCr test structures showed both rectifying DC current-voltage characteristics and linear 1/C2 vs. DC reverse bias voltage. These confirm the applicability of the C-DLTS technique for defect spectrum deconvolution and the n-type conductivity of the studied films. Isochronal annealing (30 min in argon or 60 min in nitrogen) has been performed over the temperature range 300°C - 650°C. The N(E) distribution is only slightly affected by annealing in argon. However, the distribution depends strongly on the annealing temperature in nitrogen ambient. A strong N(E) peak at Ec – E = 0.55 – 0.60 eV is detected in all samples annealed in argon but this peak is practically absent in samples annealed in nitrogen at Ta < 480°C. On the other hand, two new peaks at Ec – E = 0.12 and 0.20 eV appear in the N(E) spectrum of the samples annealed in nitrogen at Ta = 650°C. The different features of the defect spectrum are attributed to different interactions of argon and nitrogen with dangling carbon bonds on the intra-pore surfaces.