Deposits of clastic carbonate-dominated (calciclastic) sedimentary slope systems in the rock record have been identified mostly as linearly-consistent carbonate apron deposits, even though most ancient clastic carbonate slope deposits fit the submarine fan systems better. Calciclastic submarine fans are consequently rarely described and are poorly understood. Subsequently, very little is known especially in mud-dominated calciclastic submarine fan systems. Presented in this study are a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) that reveals a >250 m thick calciturbidite complex deposited in a calciclastic submarine fan setting. Seven facies are recognised from core and thin section characterisation and are grouped into three carbonate turbidite sequences. They include: 1) Calciturbidites, comprising mostly of highto low-density, wavy-laminated bioclast-rich facies; 2) low-density densite mudstones which are characterised by planar laminated and unlaminated muddominated facies; and 3) Calcidebrites which are muddy or hyper-concentrated debrisflow deposits occurring as poorly-sorted, chaotic, mud-supported floatstones. These

Phd by thesis

The present invention provides stretchable, and optionally printable, semiconductors and electronic circuits capable of providing good performance when stretched, compressed, flexed or otherwise deformed. Stretchable semiconductors and electronic circuits of the present invention preferred for some applications are flexible, in addition to being stretchable, and thus are capable of significant elongation, flexing, bending or other deformation along one or more axes. Further, stretchable semiconductors and electronic circuits of the present invention may be adapted to a wide range of device configurations to provide fully flexible electronic and optoelectronic devices.

http://science.sciencemag.org/content/sci/311/5758/208.full.pdf

Stretchable form of single crystal silicon for high performance electronics on rubber substrates

The present invention provides methods, systems and system components for transferring, assembling and integrating features and arrays of features having selected nanosized and/or microsized physical dimensions, shapes and spatial orientations. Methods of the present invention utilize principles of ‘soft adhesion’ to guide the transfer, assembly and/or integration of features, such as printable semiconductor elements or other components of electronic devices. Methods of the present invention are useful for transferring features from a donor substrate to the transfer surface of an elastomeric transfer device and, optionally, from the transfer surface of an elastomeric transfer device to the receiving surface of a receiving substrate. The present methods and systems provide highly efficient, registered transfer of features and arrays of features, such as printable semiconductor element, in a concerted manner that maintains the relative spatial orientations of transferred features.

Pattern Transfer Printing by Kinetic Control of Adhesion to an Elastomeric Stamp

The present invention provides device components geometries and fabrication strategies for enhancing the electronic performance of electronic devices based on thin films of randomly oriented or partially aligned semiconducting nanotubes. In certain aspects, devices and methods of the present invention incorporate a patterned layer of randomly oriented or partially aligned carbon nanotubes, such as one or more interconnected SWNT networks, providing a semiconductor channel exhibiting improved electronic properties relative to conventional nanotubes-based electronic systems.

Medium scale carbon nanotube thin film integrated circuits on flexible plastic substrates

In this thesis, the existence and uniqueness of gradient trajectories near an A2singularity are analysed. The A2-singularity is called a birth-death critical point in the real case. The birth-death critical point appears in a one-parameter family of functions. Such a family of functions has precisely two Morse critical points of index difference one, on the birth side. The result of the real case states that these two critical points are joined by a unique gradient trajectory up to time-shift. Here the gradient flow is defined with respect to any family of Riemannian metrics. This can be viewed as a converse to Smale’s cancellation theorem. We also look at the complex analogue of the result in Picard–Lefschetz theory. This analogue considers a holomorphic one-parameter family with an A2-singularity. Such a family has two critical Morse critical points near the singularity for every small non-zero parameter. We prove that the two Lagrangian vanishing cycles associated to these critical points intersect transversally in exactly one point in all regular fibres along a straight line. The result is obtained by analysing the gradient trajectories of the real part of these functions. Both proofs start with a normal form in local coordinates for such families of functions. The gradient equations in these coordinates can be rescaled into a fast-slow system of non-linear differential equation. Existence will rely on an adiabatic limit analysis whereas uniqueness follows from a Conley index pair construction. The latter construction will also show that connecting gradient trajectories cannot leave the local charts. Even though the proof of these two results follow from similar lines of argument, the real case cannot be reduced to the complex case and vice versa.

Doctoral Thesis by

Inexpensive, easy-to-process, light-weight polymer-based materials that are biocompatible, mechanically flexible, and optically transparent have emerged as alternatives to metals and ceramics in the packaging of implantable sensors. These materials have been used to package components such as microelectrode arrays, telemetric coils and structural membranes. Polymers are also being used for the encapsulations and coatings of the implants. The devices and packages require fine-pitch, low-loss, and highly-conductive paths on mechanically and chemically reliable polymer films. In this review, several polymers used for implantation and related integration technologies are identified. We give an overview of novel applications of polymers in implantable sensor packages, and identify future directions for their application. Polymers exhibit high moisture absorption rate, high-frequency electrical loss, and low mechanical stability. These properties are aggravated when polymers are used for in vivo applications. Also, the integration of polymers with polymers/metals at high bonding temperatures and pressures may degrade their properties and interfaces. Furthermore, adhesive bonding and physical/chemical deposition methods for the integration may introduce non-hermetic, permeable, optically opaque, and poorly conductive interfaces. Thus, creating polymer-based high-density and small-dimension structures are critical for packaging. To address these issues, polymers with improved characteristics as well as integration techniques using low bonding temperature and pressure are indispensable. Liquid crystal polymer (LCP) and surface activated bonding (SAB) technologies meet these requirements. SAB technologies enable nanoscaled polymer–polymer/metal bonding to realize reliable, miniaturized, and high-performance packages for implantable sensors. This article is meant to serve as a reference for future research in the emerging field of implantable sensors by critically assessing the specific merits and drawbacks of several material-process combinations.

/pdf/polymer-integration-for-packaging-of-implantable-sensors-4n7j5lczsx.pdf

Polymer integration for packaging of implantable sensors

The current-voltage (I-V) characteristics of two different polymer thin-film transistors (TFTs), based on spin-coating of poly(3-hexylthiophene)-P3HT and poly(3-hexadecylthiophene)-P3HDT, are studied. A model is developed to interpret the results and to explain the differences between these two polymers. Various parameters of the semiconducting polymers, including bulk mobility, field-effect mobility, trap density, and unintentional dopant concentration are estimated. The model takes into account the domination of the bulk current over the channel current in the subthreshold regime as well as the effects of the depletion layer as parasitic resistances in series with the channel resistance. Furthermore, the effects of the films thickness on the electrical characteristics of these TFTs are discussed. Compared to the P3HT, the P3HDT-based TFT has a lower subthreshold slope, higher on current ratio, and higher field-effect mobility.

Electrical characterization of polymer-based FETs fabricated by spin-coating poly(3-alkylthiophene)s

All activity in modeling transient diffusion behavior relies on knowledge of the inert intrinsic diffusivities of dopants in Si. The measurements upon which these values are based were conducted over 15 years ago. Since then, the quality of wafers used in industrial applications has significantly changed. This will affect the effective diffusivity through changes in trap concentrations. The reliability of measurement techniques has also changed dramatically from tracer and staining methods to secondary ion mass spectrometry (SIMS) measurements that are dominant today. Finally, our understanding of diffusion behavior has changed significantly. For example, we now understand that the extraction of diffusivities from implanted samples with no pre-anneal includes a significant transient effect. We have measured the inert intrinsic diffusivities of As, B, P, and Sb in different substrates in defect-free Czochralski and float zone wafers and epitaxially grown layers. All samples underwent a 30 min anneal at 100...

Accurate measurements of the intrinsic diffusivities of boron and phosphorus in silicon

InGaP nanowires (NWs) were grown by the Au-assisted method in a gas source molecular beam epitaxy system. The dependence of InGaP composition, morphology and stacking fault density was studied with respect to group III and V impingement rate and size of the Au particle. Compositional analysis showed that the NWs had an In-rich core and a Ga-rich shell structure. The In incorporation within the NW became limited as the Au seed particle size diminished or the group III and V flux decreased. The NWs had wurtzite (WZ) crystal structure with zinc blende (ZB) segments (stacking faults). The density of the stacking faults decreased as the group III flux decreased and the group V flux increased.

Dependence of InGaP nanowire morphology and structure on molecular beam epitaxy growth conditions

Silicon-germanium is an important material that is used for the fabrication of SiGe heterojunction bipolar transistors and strained Si metal-oxide-semiconductor (MOS) transistors for advanced complementary metal-oxide-semiconductor (CMOS) and BiCMOS (bipolar CMOS) technologies. It also has interesting optical properties that are increasingly being applied in silicon-based photonic devices. The key benefit of silicon-germanium is its use in combination with silicon to produce a heterojunction. Strain is incorporated into the silicon-germanium or the silicon during growth, which also gives improved physical properties such as higher values of mobility. This chapter reviews the properties of silicon-germanium, beginning with the electronic properties and then progressing to the optical properties. The growth of silicon-germanium is considered, with particular emphasis on the chemical vapour deposition technique and selective epitaxy. Finally, the properties of polycrystalline silicon-germanium are discussed in the context of its use as a gate material for MOS transistors.

Yaser M. Haddara

Papers

Polymer integration for packaging of implantable sensors

Electrical characterization of polymer-based FETs fabricated by spin-coating poly(3-alkylthiophene)s

Accurate measurements of the intrinsic diffusivities of boron and phosphorus in silicon

Dependence of InGaP nanowire morphology and structure on molecular beam epitaxy growth conditions

Silicon–Germanium: properties, growth and applications