XPS Study of Buried Metal/Polymer and Polymer/Metal Interface

1995 ◽  
Vol 385 ◽  
Author(s):  
P. K. Wu
Keyword(s):  
Integrated Circuits ◽  
Photoelectron Spectroscopy ◽  
Dielectric Material ◽  
Substrate Surface ◽  
Dielectric Constants ◽  
Ex Situ ◽  
Practical Reasons ◽  
Interlayer Dielectric ◽  
Buried Interfaces ◽  
Metal Polymer

ABSTRACTMetal/Polymer systems have potential applications as interconnect materials in integrated circuits. Polymers with low dielectric constants, if used as interlayer dielectric, can reduce the RC time constant. Device speed can be doubled if a polymer can replace the present dielectric material, SiO2. However, the problem of weak metal/polymer adhesion must be understood and resolved. In situ deposition and analysis are the most controlled means to study an interface formation process. However, for practical reasons, i.e., application, time, cost, and flexibility, it is critical to study metal/polymer interface ex situ. X-ray Photoelectron Spectroscopy (XPS), can be used to determine the composition and bonding structures of buried interfaces. This is achieved by examining peeled surfaces, thin overlayer, and lowenergy- ion sputtered surfaces. The possible adhesion mechanism or failure mode is determined by correlating XPS results with adhesion strength. Based on these results, adhesion enhancement methods, such as substrate surface treatments, can be formulated. The product of these treatments can be evaluated using the same analysis. These techniques for studying buried interfaces using XPS are reviewed and results of their applications to the metal/Teflon AF 1600 interface is presented.

Air Bridge Technology: A Comparison of Novel Interconnect Materials and Integration Schemes for Beyond 45 nm

2003 ◽  
Vol 766 ◽  
Author(s):  
Kenneth Foster ◽  
Joost Waeterloos ◽  
Don Frye ◽  
Steve Froelicher ◽  
Mike Mills
Keyword(s):  
Dielectric Constants ◽  
Advanced Technology ◽  
Effective Dielectric Constant ◽  
Device Performance ◽  
Interlayer Dielectric ◽  
Integration Schemes ◽  
Stepwise Reduction ◽  
Bridge Technology ◽  
Integrated Device ◽  
Compare And Contrast

AbstractThe electronics industry, in a continual drive for improved integrated device performance, is seeking increasingly lower dielectric constants (k) of the insulators that are used as interlayer dielectric (ILD) for advanced logic interconnects. As the industry continually seeks a stepwise reduction of the “effective” dielectric constant (keff), simple extendibility, leads to the consideration of the highest performance possible, namely air bridge technology. In this paper we will discuss requirements, integration schemes and properties for a novel class of materials that has been developed as part of an advanced technology probe into air bridge architecture. We will compare and contrast these potential technology offerings with other existing dense and porous ILD integration options, and show that the choice is neither trivial nor obvious.

CO2 Reduction to Propanol by Copper Foams: A Pre- and Post-Catalysis Study

2020 ◽  
Author(s):  
Jennifer A. Rudd ◽  
Ewa Kazimierska ◽  
Louise B. Hamdy ◽  
Odin Bain ◽  
Sunyhik Ahn ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Photoelectron Spectroscopy ◽  
Carbon Capture ◽  
Surface Composition ◽  
Co2 Reduction ◽  
Structural Rearrangement ◽  
Copper Electrode ◽  
Ex Situ ◽  
X Ray ◽  
Copper Electrodes

The utilization of carbon dioxide is a major incentive for the growing field of carbon capture. Carbon dioxide could be an abundant building block to generate higher value products. Herein, we describe the use of porous copper electrodes to catalyze the reduction of carbon dioxide into higher value products such as ethylene, ethanol and, notably, propanol. For <i>n</i>-propanol production, faradaic efficiencies reach 4.93% at -0.83 V <i>vs</i> RHE, with a geometric partial current density of -1.85 mA/cm<sup>2</sup>. We have documented the performance of the catalyst in both pristine and urea-modified foams pre- and post-electrolysis. Before electrolysis, the copper electrode consisted of a mixture of cuboctahedra and dendrites. After 35-minute electrolysis, the cuboctahedra and dendrites have undergone structural rearrangement. Changes in the interaction of urea with the catalyst surface have also been observed. These transformations were characterized <i>ex-situ</i> using scanning electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. We found that alterations in the morphology, crystallinity, and surface composition of the catalyst led to the deactivation of the copper foams.

scholarly journals Fabrication of Eutectic Ga-In Nanowire Arrays Based on Plateau–Rayleigh Instability

Molecules ◽  
2021 ◽  
Vol 26 (15) ◽  
pp. 4616
Author(s):  
Takashi Ikuno ◽  
Zen Somei
Keyword(s):  
Integrated Circuits ◽  
Substrate Surface ◽  
Three Dimensional ◽  
Average Diameter ◽  
Nanowire Arrays ◽  
Scanning Probe ◽  
Rayleigh Instability ◽  
Simple Method ◽  
Flat Substrate ◽  
Metal Nanowire

We have developed a simple method of fabricating liquid metal nanowire (NW) arrays of eutectic GaIn (EGaIn). When an EGaIn droplet anchored on a flat substrate is pulled perpendicular to the substrate surface at room temperature, an hourglass shaped EGaIn is formed. At the neck of the shape, based on the Plateau–Rayleigh instability, the EGaIn bridge with periodically varying thicknesses is formed. Finally, the bridge is broken down by additional pulling. Then, EGaIn NW is formed at the surface of the breakpoint. In addition, EGaIn NW arrays are found to be fabricated by pulling multiple EGaIn droplets on a substrate simultaneously. The average diameter of the obtained NW was approximately 0.6 μm and the length of the NW depended on the amount of droplet anchored on the substrate. The EGaIn NWs fabricated in this study may be used for three-dimensional wiring for integrated circuits, the tips of scanning probe microscopes, and field electron emission arrays.

scholarly journals Electrochemical study on nickel aluminum layered double hydroxides as high-performance electrode material for lithium-ion batteries based on sodium alginate binder

2021 ◽  
Author(s):  
Xinyue Li ◽  
Marco Fortunato ◽  
Anna Maria Cardinale ◽  
Angelina Sarapulova ◽  
Christian Njel ◽  
...  
Keyword(s):  
Lithium Ion Batteries ◽  
Electrode Material ◽  
Photoelectron Spectroscopy ◽  
Negative Electrode ◽  
Lithium Ion ◽  
Electrochemical Study ◽  
Ex Situ ◽  
Potential Range ◽  
X Ray ◽  
Storage Mechanism

AbstractNickel aluminum layered double hydroxide (NiAl LDH) with nitrate in its interlayer is investigated as a negative electrode material for lithium-ion batteries (LIBs). The effect of the potential range (i.e., 0.01–3.0 V and 0.4–3.0 V vs. Li+/Li) and of the binder on the performance of the material is investigated in 1 M LiPF6 in EC/DMC vs. Li. The NiAl LDH electrode based on sodium alginate (SA) binder shows a high initial discharge specific capacity of 2586 mAh g−1 at 0.05 A g−1 and good stability in the potential range of 0.01–3.0 V vs. Li+/Li, which is better than what obtained with a polyvinylidene difluoride (PVDF)-based electrode. The NiAl LDH electrode with SA binder shows, after 400 cycles at 0.5 A g−1, a cycling retention of 42.2% with a capacity of 697 mAh g−1 and at a high current density of 1.0 A g−1 shows a retention of 27.6% with a capacity of 388 mAh g−1 over 1400 cycles. In the same conditions, the PVDF-based electrode retains only 15.6% with a capacity of 182 mAh g−1 and 8.5% with a capacity of 121 mAh g−1, respectively. Ex situ X-ray photoelectron spectroscopy (XPS) and ex situ X-ray absorption spectroscopy (XAS) reveal a conversion reaction mechanism during Li+ insertion into the NiAl LDH material. X-ray diffraction (XRD) and XPS have been combined with the electrochemical study to understand the effect of different cutoff potentials on the Li-ion storage mechanism. Graphical abstract The as-prepared NiAl-NO3−-LDH with the rhombohedral R-3 m space group is investigated as a negative electrode material for lithium-ion batteries (LIBs). The effect of the potential range (i.e., 0.01–3.0 V and 0.4–3.0 V vs. Li+/Li) and of the binder on the material’s performance is investigated in 1 M LiPF6 in EC/DMC vs. Li. Ex situ X-ray photoelectron spectroscopy (XPS) and ex situ X-ray absorption spectroscopy (XAS) reveal a conversion reaction mechanism during Li+ insertion into the NiAl LDH material. X-ray diffraction (XRD) and XPS have been combined with the electrochemical study to understand the effect of different cutoff potentials on the Li-ion storage mechanism. This work highlights the possibility of the direct application of NiAl LDH materials as negative electrodes for LIBs.

scholarly journals A hybrid broadband metalens operating at ultraviolet frequencies

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Farhan Ali ◽  
Serap Aksu
Keyword(s):  
Dielectric Material ◽  
Berry Phase ◽  
Uv Light ◽  
Fdtd Method ◽  
Numerical Aperture ◽  
Limited Range ◽  
Unit Cell ◽  
Dielectric Constants ◽  
Phase Method ◽  
Frequency Range

AbstractThe investigation on metalenses have been rapidly developing, aiming to bring compact optical devices with superior properties to the market. Realizing miniature optics at the UV frequency range in particular has been challenging as the available transparent materials have limited range of dielectric constants. In this work we introduce a low absorption loss and low refractive index dielectric material magnesium oxide, MgO, as an ideal candidate for metalenses operating at UV frequencies. We theoretically investigate metalens designs capable of efficient focusing over a broad UV frequency range (200–400 nm). The presented metalenses are composed of sub-wavelength MgO nanoblocks, and characterized according to the geometric Pancharatnam–Berry phase method using FDTD method. The presented broadband metalenses can focus the incident UV light on tight focal spots (182 nm) with high numerical aperture ($$\hbox {NA}\approx 0.8$$ NA ≈ 0.8 ). The polarization conversion efficiency of the metalens unit cell and focusing efficiency of the total metalens are calculated to be as high as 94%, the best value reported in UV range so far. In addition, the metalens unit cell can be hybridized to enable lensing at multiple polarization states. The presented highly efficient MgO metalenses can play a vital role in the development of UV nanophotonic systems and could pave the way towards the world of miniaturization.

Composition and Structure of Epitaxial CaF2 Layers at the First Stages of Their Growth on Si(111)

2001 ◽  
Vol 696 ◽  
Author(s):  
R. Würz ◽  
W. Bohne ◽  
W. Fuhs ◽  
J. Röhrich ◽  
M. Schmidt ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Film Growth ◽  
Stoichiometric Composition ◽  
Interface Reaction ◽  
Heavy Ion ◽  
Interface Layer ◽  
Buffer Layers ◽  
Ex Situ ◽  
Elastic Recoil ◽  
Detection Analysis

AbstractCaF2 films with thicknesses in the monolayer range (<20 Å) were grown on Si(111) by evaporation from a CaF2 source at UHV conditions. They were characterized ex-situ by Heavy-Ion Elastic Recoil Detection Analysis (HI-ERDA), RBS/Channeling, X-ray Photoelectron Spectroscopy (XPS) and Atomic Force Microscopy (AFM). The F/Ca ratio of the films was found to depend on the growth temperature Ts and to deviate appreciably from the stoichiometric composition (F/Ca=2). Due to an interface reaction which leads to a CaF-interface layer a change from polycrystalline to epitaxial growth occurs at Ts=450°C. At higher temperature film growth started with a closed layer of CaF on top of which CaF2 layers with an increasing fraction of pinholes were formed. By means of a two-step process at different temperatures, the amount of pinholes could be strongly reduced. It was found, that buffer layers of CaF2 with a CaF interface layer introduced in Au/p-Si contacts enhance the barrier height by as much as 0.36eV to values of 0.64eV.

On The Optimized Nucleation of Near-Single-Crystal Cvd Diamond Film

1995 ◽  
Vol 416 ◽  
Author(s):  
L. C. Chen ◽  
C. C. Juan ◽  
J. Y. Wu ◽  
K. H. Chen ◽  
J. W. Teng
Keyword(s):  
Single Crystal ◽  
Photoelectron Spectroscopy ◽  
Morphological Evolution ◽  
Present Report ◽  
Ex Situ ◽  
Nucleation Density ◽  
Induced Current ◽  
Current Time ◽  
Single Crystal Diamond

ABSTRACTNear-single-crystal diamond films have been obtained in a number of laboratories recently. The optimization of nucleation density by using a bias-enhanced nucleation (BEN) method is believed to be a critical step. However, the condition of optimized nucleation has never been clearly delineated. In the present report, a novel quantitative technique was established to monitor the nucleation of diamond in-situ. Specifically, the induced current was measured as a function of nucleation time during BEN. The timedependence of induced current was studied under various methane concentrations as well as substrate temperatures. The optimized nucleation condition can be unambiguously determined from the current-time plot. Besides the in-situ current probe, ex-situ x-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) were also used to investigate the chemical and morphological evolution. Characteristic XPS and AFM features of optimized nucleation is discussed.

A look into the interaction of metal oxide thin films with biological media: Albumin and Fibrinogen adsorption

2012 ◽  
Vol 1376 ◽  
Author(s):  
P. Silva-Bermudez ◽  
S. Muhl ◽  
M. Rivera ◽  
S. E. Rodil
Keyword(s):  
Surface Roughness ◽  
Surface Energy ◽  
Protein Adsorption ◽  
Photoelectron Spectroscopy ◽  
Ex Situ ◽  
Polar Component ◽  
Metal Oxide Thin Films ◽  
Adsorbed Protein ◽  
Major Chemical ◽  
Fibrinogen Adsorption

ABSTRACTIn the present work, the adsorption of albumin and fibrinogen on Ta, Nb, Ti and Zr oxidesthin films deposited on Si (100) wafers by magnetron sputtering was studied in order to get a better understanding of the correlation among the surface properties of these oxides and the protein adsorption phenomena on their surfaces. The surface energy, hydrophobicity, chemical composition, roughness and atomic order of the films were characterized. The films were immersedfor 45 minutes in single protein solutions; either albumin or fibrinogenand the adsorbed protein layer on the films was studied ex-situ in a dry ambient using bothX-ray photoelectron spectroscopy and atomic force microscopy.The adsorption of albumin and fibrinogen on the films modified the surface morphology and decreased the surface roughness for all the four different metal oxides. The XPS results confirmed the presence of the protein on the surface of the films and showed that the two proteins studied were adsorbed without undergoing a major chemical decomposition. A correlation between the surface roughness,the polar component of the surface energy of the films and the atomic percentage of nitrogen on the films after protein adsorption, an indirect signal of the amount of protein adsorbed, was found for albumin and fibrinogen adsorption on Ta, Nb and Ti oxides; the largest the roughness or the polar component the largest amount of adsorbed protein.

Inlaid Copper Multilevel Interconnections Using Planarization by Chemical-Mechanical Polishing

MRS Bulletin ◽  
1993 ◽  
Vol 18 (6) ◽  
pp. 46-51 ◽  
Author(s):  
S.P. Murarka ◽  
J. Steigerwald ◽  
R.J. Gutmann
Keyword(s):  
Integrated Circuits ◽  
Large Scale ◽  
Ohmic Contacts ◽  
Access Time ◽  
Gigascale Integration ◽  
Interlayer Dielectric ◽  
Application Specific Integrated Circuits ◽  
Large Scale Integration ◽  
Scale Integration ◽  
Application Specific

Continuing advances in the fields of very-large-scale integration (VLSI), ultralarge-scale integration (ULSI), and gigascale integration (GSI), leading to the continuing development of smaller and smaller devices, have continually challenged the fields of materials, processes, and circuit designs. The existing metallization schemes for ohmic contacts, gate metal, and interconnections are inadequate for the ULSI and GSI era. An added concern is the reliability of aluminum and its alloys as the current carrier. Also, the higher resistivity of Al and its use in two-dimensional networks have been considered inadequate, since they lead to unacceptably high values of the so-called interconnection delay or RC delay, especially in microprocessors and application-specific integrated circuits (ICs). Here, R refers to the resistance of the interconnection and C to the total capacitance associated with the interlayer dielectric. For the fastest devices currently available and faster ones of the future, the RC delay must be reduced to such a level that the contribution of RC to switching delays (access time) becomes a small fraction of the total, which is a sum of the inherent device delay associated with the semiconductor, the device geometry and type, and the RC delay.

Silk Polymer Coating with Low Dielectric Constant and High Thermal Stability for Ulsi Interlayer Dielectric

1997 ◽  
Vol 476 ◽  
Author(s):  
P. H. Townsend ◽  
S. J. Martin ◽  
J. Godschalx ◽  
D. R. Romer ◽  
D. W. Smith ◽  
...  
Keyword(s):  
Thin Film ◽  
Dielectric Constant ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Integrated Circuits ◽  
Room Temperature ◽  
Polymer Network ◽  
Flow Characteristics ◽  
Interlayer Dielectric

AbstractA novel polymer has been developed for use as a thin film dielectric in the interconnect structure of high density integrated circuits. The coating is applied to the substrate as an oligomeric solution, SiLK*, using conventional spin coating equipment and produces highly uniform films after curing at 400 °C to 450 °C. The oligomeric solution, with a viscosity of ca. 30 cPs, is readily handled on standard thin film coating equipment. Polymerization does not require a catalyst. There is no water evolved during the polymerization. The resulting polymer network is an aromatic hydrocarbon with an isotropie structure and contains no fluorine.The properties of the cured films are designed to permit integration with current ILD processes. In particular, the rate of weight-loss during isothermal exposures at 450 °C is ca. 0.7 wt.%/hour. The dielectric constant of cured SiLK has been measured at 2.65. The refractive index in both the in-plane and out-of-plane directions is 1.63. The flow characteristics of SiLK lead to broad topographic planarization and permit the filling of gaps at least as narrow as 0.1 μm. The glass transition temperature for the fully cured film is greater than 490 °C. The coefficient of thermal expansivity is 66 ppm/°C below the glass transition temperature. The stress in fully cured films on Si wafers is ca. 60 MPa at room temperature. The fracture toughness measured on thin films is 0.62 MPa m ½. Thin coatings absorb less than 0.25 wt.% water when exposed to 80% relative humidity at room temperature.

Sign in / Sign up

Export Citation Format

Share Document