Advanced Electronic Materials Research Articles

Editorial: Awards for best X‐Ray Spectrometry referee during 2009–2010

Editorial: Awards for best <i>X‐Ray Spectrometry</i> referee during 2009–2010

ChemInform Abstract: Electrochemical Aspects of Advanced Electronic Materials

Abstract Electrochemical ideas and techniques are widely used in advanced electronic materials. As one of the most representative types of highly functional materials, magnetic recording materials are introduced and reviewed to illustrate the potential of electrochemical techniques.

Expanding the Realm of Furan-Based Conducting Polymers through Conjugation with 1,6-Methano[10]annulene

The synthesis of a new bisfuranyl monomer, 2,7-bis(2-furanyl)-1,6-methano[10]annulene, is presented. Its properties and those of its polymer, synthesized via electropolymerization, are compared to those of the known furan−arene−furan monomers and their respective polymers. Investigation using UV−vis spectroscopy, cyclic voltammetry, and spectroelectrochemistry indicated that the 1,6-methano[10]annulene copolymer has properties rivaling those of the copolymers containing traditional aromatic cores. These results are rationalized in conjunction with DFT calculations, and they further the premise that 1,6-methano[10]annulene can be viewed as a viable building block for advanced π-conjugated electronic materials.

PUBLISHING ACS to launch new materials science journal

In early 2009, the American Chemical Society will introduce its 36th journal, ACS Applied Materials & Interfaces. Kirk S. Schanze, a chemistry professor at the University of Florida (UF), will serve as editor of the new publication. The peer-reviewed journal will be the first ACS materials chemistry publication to “focus exclusively on applied science and engineering, as opposed to fundamental science and engineering,” Schanze says. Its articles, letters, editorial commentaries, and topical forums will cover a range of subjects, including advanced active and passive electronic and optical materials, coatings, colloids, biomaterials and bio-interfaces, polymer materials, hybrid and composite materials, and friction and wear. “With nearly 10 years’ tenure as a senior editor for the ACS journal Langmuir , collaborations with government and industrial laboratories, and broad research interests that dovetail extremely well with the scope of the journal, professor Schanze was the natural candidate for editor-in...

Mesoporous Carbon Materials: Synthesis and Modification

Porous carbon materials are of interest in many applications because of their high surface area and physicochemical properties. Conventional syntheses can only produce randomly porous materials, with little control over the pore-size distributions, let alone mesostructures. Recent breakthroughs in the preparation of other porous materials have resulted in the development of methods for the preparation of mesoporous carbon materials with extremely high surface areas and ordered mesostructures, with potential applications as catalysts, separation media, and advanced electronic materials in many scientific disciplines. Current syntheses can be categorized as either hard-template or soft-template methods. Both are examined in this Review along with procedures for surface functionalization of the carbon materials obtained.

Advanced electronic and optoelectronic materials by Atomic Layer Deposition: An overview with special emphasis on recent progress in processing of high-k dielectrics and other oxide materials

The Feature Article [1] describes the current state of the Atomic Layer Deposition (ALD) technique for producing high-quality thin layers with the focus on oxide materials such as ZrO2 and other rare earth oxides, SnO2 and ZnO for high-k dielectrics, gas sensors and various optoelectronic applications. The cover picture is a photograph of a thin-film-on-silicon sample. The inset schematically illustrates the ALD growth of an oxide film on a surface where L refers to the precursor ligand. The first author, Lauri Niinisto, is Professor of Inorganic Chemistry at Helsinki University of Technology. His current research is focused on the preparation and characterization of thin films for optoelectronic and electronic devices.

Feature Article: Advanced electronic and optoelectronic materials by Atomic Layer Deposition: An overview with special emphasis on recent progress in processing of high-k dielectrics and other oxide materials

The Feature Article [1] describes the current state of the Atomic Layer Deposition (ALD) technique for producing high-quality thin layers with the focus on oxide materials such as ZrO2 and other rare earth oxides, SnO2 and ZnO for high-k dielectrics, gas sensors and various optoelectronic applications. The cover picture is a photograph of a thin-film-on-silicon sample. The inset schematically illustrates the ALD growth of an oxide film on a surface where L refers to the precursor ligand. The first author, Lauri Niinistö, is Professor of Inorganic Chemistry at Helsinki University of Technology. His current research is focused on the preparation and characterization of thin films for optoelectronic and electronic devices.

A low-viscousity, highly thermally conductive epoxy molding compound (EMC)

Advanced epoxy molding compounds (EMCs) should be considered to alleviate the thermal stress problems caused by low thermal conductivity and high elastic modulus of an EMC and by the mismatch of the coefficient of thermal expansion (CTE) between an EMC and the Si-wafer. Though AlN has some advantages, such as high thermal conductivity and mechanical strength, an AlN-filled EMC could not be applied to commercial products because of its low fluidity and high modulus. To solve this problem, we used 2-μm fused silica, which has low porosity and spherical shape, as a small size filler in the binary mixture of fillers. When the composition of the silica in the binary filler system reached 0.3, the fluidity of EMC was improved more than twofold and the mechanical strength was improved 1.5 times, relative to the 23-μm AlN-filled EMC. In addition, the values of the elastic modulus and the dielectric constant were reduced to 90%, although the thermal conductivity of EMC was reduced from 4.3 to 2.5W/m-K, when compared with the 23μm AlN-filled EMC. Thus, the AlN/silica (7/3)-filled EMC effectively meets the requirements of an advanced electronic packaging material for commercial products, such as high thermal conductivity (more than 2W/m-K), high fluidity, low elastic modulus, low dielectric constant, and low CTE.

Nanoindentaion techniques for assessing mechanical reliability at the nanoscale

Nanoindetation is a powerful technique for measuring mechanical properties of thin films. First applied over 20 years ago in the hard drive industry, it is now commonly used for other applications. This paper describes nanoindentation techniques for measuring thin films mechanical properties, including elastic modulus, hardness, adhesion and fracture toughness as applied for modern microelectronics reliability. Elastic, plastic and adhesion properties of Cu interconnects are discussed, including the influence of film microstructure, thickness and grain size. Elastic, fracture and adhesion properties of advanced low- K dielectrics also discussed along with the current challenges of nanoindentation data interpretation and analysis as applied for advanced electronic materials.

DOW REARRANGES A KEY PORTFOLIO

DOW CHEMICAL IS CHANGING the way it approaches its portfolio, a family of high-value, end-market-oriented businesses that the company considers key to its future growth. In conjunction with the retirement of Ed F. Gambrell, 59, president of the market-facing businesses group, Dow is disbanding the portfolio and giving responsibility to other senior executives. Dow Automotive, the largest of the market-facing units, with about $1 billion in annual sales, will become part of Dow's thermosets business, headed by Robert L. Wood. The market-facing advanced electronic materials unit, which includes SiLK semi-conductor resins and Lumation polymeric light-emitting diodes, will fall under David E. Kepler, Dow's chief information officer and vice president for e-business. Richard M. Gross, vice president for R&D, will assume responsibility for the new business activities now under Gambrell. These include industrial biotechnology, pharmaceutical technologies, Dow's new business growth board, and its ...

Functional oligothiophenes as advanced molecular electronic materials

The oligothiophene/fullerene dyad system shows marked photoinduced electron transfer from the oligomer to the attached fullerene at the terminal position, and is successfully put to practical use in the fabrication of photovoltaic cells. The further modified dyad system, attaching a thiol or disulfide anchoring group at another terminal position, can form a self-assembled monolayer (SAM) on a gold substrate, where the tethered molecules are unidirectionally ordered. In particular, the use of a tripodal anchoring group provides a powerful approach for the formation of a much denser and more stable SAM, which is beneficial for the high performance of SAM-based photovoltaic cells. The porphyrin/oligothiophene/fullerene triad system is designed to evaluate efficient intramolecular electron transfer from the terminal porphyrin to the other terminal fullerene through the central oligothiophene, revealing the high potential of oligothiophene as a long-range molecular wire. Other oligothiophenes incorporating pyrenes or terpyridines are developed as light-emitting materials useful for electroluminescent (EL) devices. In these devices, the pyrene-modified system also acts as a hole-transport layer, whereas the terpyridine-modified system acts as an electron-transport layer.

Research trends

Diamond has attractive properties as an advanced electronic material. Its combination of high carrier mobility, electric breakdown, and thermal conductivity results in the largest calculated figures of merit for speed and power of any material. Previously (J.L. Davidson, W.P. Kang, Examples of diamond sensing applications, Proceedings 3rd International Symposium on Diamond Film (ISDF-3), Polytechnical Institute of Russian Academy of Science, St. Petersburg, Russia, 16–19 June 1996) we reported the discovery and development of useful ‘secondary’ effects in diamond and applying them to interesting sensor applications. For example, boron-doped diamond piezoresistors for strain micro-gauges on rugged MEMS (microelectromechanical structures) pressure and acceleration sensors. This paper will present some recent developments with chemically vapor-deposited diamond for microelectromechanical sensing applications such as a new design all diamond pressure microsensor that measures pressure at high temperatures and an accelerometer with over 45 kHz resonant frequency. Also, presented are recent results on layered diamond films that behave as chemical sensors measuring hydrogen, oxygen and many other chemicals’ concentration. For example, a diamond-based chemical gas sensor using Pt/SnOx/i-diamond/p+-diamond metal–insulator–semiconductor diode structure for oxygen sensing is described. In addition, the latest emission properties of fabricated diamond microtips for field emitters are reviewed.

Synthesis of Bis(Alkyltelluro)Methanes and their Complexation with Cadmium(II)

A novel and convenient route for the synthesis of a series of bis(alkyltelluro)methanes (alkyl─ethyl, isopropyl, n-butyl and n-hexyl) is described by one pot methylene insertion reaction using dialkyl ditellurides, sodium borohydride and chloroform. The cadmium(II) complexes of bis(isopropyltelluro)methane were also synthesized. The bis(alkyltelluro)meth-anes were characterized by elemental analysis, 1H and 125Te NMR. The product of the complexation of bis(isopropyl telluro)methane with Cd(II) have been characterized by elemental analysis, 1H, TGA and FAB mass spectrometry. The dialkyltelluroether ligands may be useful in organic synthesis and their complexes with cadmium(II) can be considered a potential single source of metal-organic chemical vapor deposition (MOCVD) precursors for advanced electronic materials.

Business introduces advanced electronic substrate materials to serve emerging markets with enabling technologies for high-performance applications

Business introduces advanced electronic substrate materials to serve emerging markets with enabling technologies for high-performance applications

Diamond as an active sensor material

Abstract Diamond has attractive properties as an advanced electronic material. Its combination of high carrier mobility, electric breakdown, and thermal conductivity results in the largest calculated figures of merit for speed and power of any material. Previously (J.L. Davidson, W.P. Kang, Examples of diamond sensing applications, Proceedings 3rd International Symposium on Diamond Film (ISDF-3), Polytechnical Institute of Russian Academy of Science, St. Petersburg, Russia, 16–19 June 1996) we reported the discovery and development of useful ‘secondary’ effects in diamond and applying them to interesting sensor applications. For example, boron-doped diamond piezoresistors for strain micro-gauges on rugged MEMS (microelectromechanical structures) pressure and acceleration sensors. This paper will present some recent developments with chemically vapor-deposited diamond for microelectromechanical sensing applications such as a new design all diamond pressure microsensor that measures pressure at high temperatures and an accelerometer with over 45 kHz resonant frequency. Also, presented are recent results on layered diamond films that behave as chemical sensors measuring hydrogen, oxygen and many other chemicals’ concentration. For example, a diamond-based chemical gas sensor using Pt/SnO x /i-diamond/p + -diamond metal–insulator–semiconductor diode structure for oxygen sensing is described. In addition, the latest emission properties of fabricated diamond microtips for field emitters are reviewed.

Quantum mechanical description of quantum well MOSFET in silicon-on-insulator technology

The limitation of the semiclassical description of the charge distribution in the thin, strained buried overlayer of the silicon-on-insulator (SOI) substrate is seen as a hinderance to the progress in device modelling and engineering when using this advanced electronic material technology. A self-consistent solution of the Schrödinger and Poisson equation is carried out to determine the hole distribution in the SiGe quantum well (QW) with a positively and negatively graded trapezoidal Ge profile grown on a SOI substrate. From a thorough analysis of the gate charge control, we predict that the improved hole confinement and channel mobility in the SiGe QW can be maximized over a wide gate voltage range using a negatively graded trapezoidal Ge profile. In addition a much thinner silicon cap layer thickness, with reduced interface scattering, can be used for the retrograded Ge profile.

Electron Transfer in Self-Assembled Inorganic Polyelectrolyte/Metal Nanoparticle Heterostructures

The way in which molecular building blocks are arranged within supramolecular structures has a marked effect on their chemical and physical properties.1 The development of techniques for controlling the spatial arrangement of the individual components of a composite material on the nanometer and subnanometer levels is, therefore, crucial to the design and fabrication of advanced electronic, optical, and mechanical materials. Basic design strategies for building supramolecular systems that have appeared in recent years involve control of hydrogen bonding,2 polymerization in layered solids,3 and thinfilm assembly on solid supports via sequential complexation reactions4 or ion exchange.5 We recently reported a simple method for assembling multilayer thin films from single anionic sheets of lamellar inorganic solids (e.g., R-Zr(HPO4)2‚H2O (R-ZrP)) and organic polyelectrolyte cations (poly(allylamine hydrochloride) (PAH)).5e The method is similar to one reported earlier by Decher and co-workers,5d except that the replacement of organic polyanions by two-dimensional sheets prevents mixing of the components of adjacent layers.5g We describe here an extension of this layerby-layer assembly scheme to the fabrication of metal-insulator-gold nanocluster-insulator-metal (MINIM) heterostructures. The MINIM structure is analogous to two parallel plate capacitors in series. An important difference between a MINIM device and a conventional, macroscale capacitor is that the small gold particle diameter (2.5 ( 1.5 nm) produces capacitances of only ∼10-18 F, thus allowing the observation of single electron charging effects at ambient temperatures. Previous work describing these effects is summarized briefly below.6 Classically, the capacitance of a metal-insulator-spherical metal particle junction is given by (1),6i where 0 is the vacuum

Examples of Diamond Sensing Applications

ABSTRACTDiamond has attractive properties as an advanced electronic material. Its combination of high carrier mobility, electric breakdown, and thermal conductivity results in the largest calculated figures of merit for speed and power of any material. Recently, the discovery and development of what might be called sophisticated secondary effects in diamond, are opening interesting sensor applications. Boron doped diamond will change electrical resistance with strain (piezoresistance), meaning it can be used as a strain gauge on rugged electronic microsensors for pressure and acceleration sensing. This paper will present some critical issues of diamond for microelectromechanical sensing applications such as its rupture stress and edge stress of diamond diaphragms and the high temperature responses of a diamond pressure sensor. We will describe an all diamond pressure microsensor that measures pressure at more than 300°C. Also, we have observed that layered diamond films can behave as chemical sensors measuring hydrogen, oxygen and many other chemicals’ concentration. For example, a diamond-based chemical gas sensor using Pd/i-diamond/p+-diamond metal-insulator-semiconductor diode structure has been made and the behavior of a new diamond-based chemical gas sensor has been studied. Also, the creation and properties of diamond microtips as field emitters are discussed.

Functionalized conjugating polymers: From molecule and ions transporting membranes to advanced electronic and photonic materials

Abstract

Deposition of Oxide Based Advanced Electronic and Optical Materials by Rapid Isothermal Processing (RIP) Assisted Metalorganic Chemical Vapor Deposition (MOCVD)

ABSTRACTMetalorganic chemical vapor deposition (MOCVD) is an ideal technique for the deposition of conducting and non-conducting oxide based thin film materials. In this paper we present our study of RIP assisted MOCVD for the low temperature deposition of a number of oxide based advanced materials which are useful for the development of the next generation of microelectronic and optoelectronic devices. We have designed several experiments to understand the role of photoeffects in RIP assisted MOCVD. The vacuum ultraviolet, ultraviolet and visible (λ ≤ 0.7–0.8μm) photons can have several beneficial effects including the enhancement of the surface reactions of the absorbed molecules through the perturbation of the electronic state of binding between the absorbed molecules and the solid surface. We have shown a direct relationship between the structural and electrical characteristics of the deposited oxide and the spectral contents of the energy source.