Chapter 11 Dopant Profiling in Semiconductor Nanoelectronics
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New Imaging Modes for Analyzing Suspended Ultra-Thin Membranes by Double-Tip Scanning Probe Microscopy Kenan Elibol1,4, Stefan Hummel1,4, Bernhard C
www.nature.com/scientificreports OPEN New imaging modes for analyzing suspended ultra-thin membranes by double-tip scanning probe microscopy Kenan Elibol1,4, Stefan Hummel1,4, Bernhard C. Bayer1,2 & Jannik C. Meyer1,3* Scanning probe microscopy (SPM) techniques are amongst the most important and versatile experimental methods in surface- and nanoscience. Although their measurement principles on rigid surfaces are well understood and steady progress on the instrumentation has been made, SPM imaging on suspended, fexible membranes remains difcult to interpret. Due to the interaction between the SPM tip and the fexible membrane, morphological changes caused by the tip can lead to deformations of the membrane during scanning and hence signifcantly infuence measurement results. On the other hand, gaining control over such modifcations can allow to explore unknown physical properties and functionalities of such membranes. Here, we demonstrate new types of measurements that become possible with two SPM instruments (atomic force microscopy, AFM, and scanning tunneling microscopy, STM) that are situated on opposite sides of a suspended two-dimensional (2D) material membrane and thus allow to bring both SPM tips arbitrarily close to each other. One of the probes is held stationary on one point of the membrane, within the scan area of the other probe, while the other probe is scanned. This way new imaging modes can be obtained by recording a signal on the stationary probe as a function of the position of the other tip. The frst example, which we term electrical cross- talk imaging (ECT), shows the possibility of performing electrical measurements across the membrane, potentially in combination with control over the forces applied to the membrane. -
DNA in Nanotechnology
Molecular Manipulations DNA in Nanotechnology There is an avalanche-like increase of reports, where molecules of nucleic acids (DNA and RNA) appear as an object of nanotechnology research and/or as material for nano-sized devices. In many cases scanning probe microscopy (SPM) is the most powerful and informative research tool. Examinations as well as precise manipulations can be performed this way. What is important when SPM is applied to molecular level experiments? Three facets are illustrated further. • Appropriate probes see the next page • Substrates and deposition protocols see page 3 • AFM long-term stability see page 4 www.ntmdt.com 1 Molecular Manipulations Probe sharpness determines resolution AFM probe tip DNA molecule 10-20nm Strand width is usually seen in AFM image Tiny features of the relief can not be detected if the probe tip radius is too large. When imaged with conventional probe, the width of the DNA molecule is 10-20 nm usually, while real strand diameter is about 2 nm. Here are shown short poly(dG)–poly(dC) DNA fragments deposited on modified HOPG (see below). Small unwound single-strand fragments can be seen (bold arrow on the scan) and even helical pitch of the DNA molecule can be resolved (thin arrows) with a sharp enough tip (like DLC probe tip shown on the inlet). See comprehensive discussion on sub-molecular imaging in “High- resolution atomic force microscopy of duplex and triplex DNA molecules” Klinov D. et al. Nanotechnology (2007), V18, N22, p.225102. Related info: 1 micron-long Whisker tip grown on silicon probe apex Whisker-type sharp AFM probes provides extremely high aspect ratio, tip radius is about 10 nm. -
CHAPTER 8: Diffusion
1 Chapter 8 CHAPTER 8: Diffusion Diffusion and ion implantation are the two key processes to introduce a controlled amount of dopants into semiconductors and to alter the conductivity type. Figure 8.1 compares these two techniques and the resulting dopant profiles. In the diffusion process, the dopant atoms are introduced from the gas phase of by using doped-oxide sources. The doping concentration decreases monotonically from the surface, and the in-depth distribution of the dopant is determined mainly by the temperature and diffusion time. Figure 8.1b reveals the ion implantation process, which will be discussed in Chapter 9. Generally speaking, diffusion and ion implantation complement each other. For instance, diffusion is used to form a deep junction, such as an n-tub in a CMOS device, while ion implantation is utilized to form a shallow junction, like a source / drain junction of a MOSFET. Boron is the most common p-type impurity in silicon, whereas arsenic and phosphorus are used extensively as n-type dopants. These three elements are highly soluble in silicon with solubilities exceeding 5 x 1020 atoms / cm3 in the diffusion temperature range (between 800oC and 1200oC). These dopants can be introduced via several means, including solid sources (BN for B, As2O3 for As, and P2O5 for P), liquid sources (BBr3, AsCl3, and POCl3), and gaseous sources (B2H6, AsH3, and PH3). Usually, the gaseous source is transported to the semiconductor surface by an inert gas (e.g. N2) and is then reduced at the surface. 2 Chapter 8 Figure 8.1: Comparison of (a) diffusion and (b) ion implantation for the selective introduction of dopants into a semiconductor substrate. -
Contactless, Nondestructive Determination of Dopant Profiles Of
www.nature.com/scientificreports OPEN Contactless, nondestructive determination of dopant profles of localized boron-difused regions in Received: 11 November 2018 Accepted: 9 July 2019 silicon wafers at room temperature Published: xx xx xxxx Hieu T. Nguyen , Zhuofeng Li, Young-Joon Han , Rabin Basnet, Mike Tebyetekerwa , Thien N. Truong , Huiting Wu, Di Yan & Daniel Macdonald We develop a photoluminescence-based technique to determine dopant profles of localized boron- difused regions in silicon wafers and solar cell precursors employing two excitation wavelengths. The technique utilizes a strong dependence of room-temperature photoluminescence spectra on dopant profles of difused layers, courtesy of bandgap narrowing efects in heavily-doped silicon, and diferent penetration depths of the two excitation wavelengths in silicon. It is fast, contactless, and nondestructive. The measurements are performed at room temperature with micron-scale spatial resolution. We apply the technique to reconstruct dopant profles of a large-area (1 cm × 1 cm) boron-difused sample and heavily-doped regions (30 μm in diameter) of passivated-emitter rear localized-difused solar cell precursors. The reconstructed profles are confrmed with the well- established electrochemical capacitance voltage technique. The developed technique could be useful for determining boron dopant profles in small doped features employed in both photovoltaic and microelectronic applications. An attractive approach for improving light-to-electricity power conversion efciencies of crystalline silicon (c-Si) solar cells is to minimize surface areas of heavily-doped layers. Tis is due to the high recombination-active nature of the heavily-doped layers, causing a signifcant loss of photo-induced electrons and holes. Several solar cell designs employing this concept have been proved to achieve efciencies over 24% such as interdigitated back-contact (IBC)1–3 and passivated-emitter rear localized-difused (PERL)4–6 cell structures. -
Low Cost Electrical Probe Station Using Etched Tungsten Nanoprobes: Role
Low cost electrical probe station using etched Tungsten nanoprobes: Role of cathode geometry Rakesh K. Prasada and Dilip K. Singha* aDepartment of Physics, Birla Institute of Technology Mesra, Ranchi-835215. *Email: [email protected] Abstract Electrical measurement of nano-scale devices and structures requires skills and hardware to make nano-contacts. Such measurements have been difficult for number of laboratories due to cost of probe station and nano-probes. In the present work, we have demonstrated possibility of assembling low cost probe station using USB microscope (US $ 30) coupled with in-house developed probe station. We have explored the effect of shape of etching electrodes on the geometry of the microprobes developed. The variation in the geometry of copper wire electrode is observed to affect the probe length and its half cone angle (1.4 to 8.8˚). These developed probes were(0.58 usedmm to 2make.15 mm contact) on micro patterned metal° films and was used for electrical measurement along with semiconductor parameter analyzer. These probes show low contact resistance (~ 4 Ω) and follows Ohmic behavior. Such probes can be used for laboratories involved in teaching and multidisciplinary research activities and Atomic Force Microscopy. Keywords: electrochemical etching, tungsten tip, DC voltage, Low cost probe station. I. INTRODUCTION Advancement in the field of nanofabrication has led to miniaturization of devices to nanometers. Research labs and teaching efforts in the field of electronics and opto-electronic devices to such small dimensions, require probes for micron or smaller size. Additionally, these factors have limited the access of experts from various domains of science and engineering to explore nanoscale structures for multi-disciplinary applications. -
Gain in Polycrystalline Nd-Doped Alumina: Leveraging Length Scales to Create a New Class of High-Energy, Short Pulse, Tunable Laser Materials Elias H
Penilla et al. Light: Science & Applications (2018) 7:33 Official journal of the CIOMP 2047-7538 DOI 10.1038/s41377-018-0023-z www.nature.com/lsa ARTICLE Open Access Gain in polycrystalline Nd-doped alumina: leveraging length scales to create a new class of high-energy, short pulse, tunable laser materials Elias H. Penilla1,2,LuisF.Devia-Cruz1, Matthew A. Duarte1,2,CoreyL.Hardin1,YasuhiroKodera1,2 and Javier E. Garay1,2 Abstract Traditionally accepted design paradigms dictate that only optically isotropic (cubic) crystal structures with high equilibrium solubilities of optically active ions are suitable for polycrystalline laser gain media. The restriction of symmetry is due to light scattering caused by randomly oriented anisotropic crystals, whereas the solubility problem arises from the need for sufficient active dopants in the media. These criteria limit material choices and exclude materials that have superior thermo-mechanical properties than state-of-the-art laser materials. Alumina (Al2O3)isan ideal example; it has a higher fracture strength and thermal conductivity than today’s gain materials, which could lead to revolutionary laser performance. However, alumina has uniaxial optical proprieties, and the solubility of rare earths (REs) is two-to-three orders of magnitude lower than the dopant concentrations in typical RE-based gain media. We present new strategies to overcome these obstacles and demonstrate gain in a RE-doped alumina (Nd:Al2O3) for the first time. The key insight relies on tailoring the crystallite size to other important length scales—the wavelength of 1234567890():,; 1234567890():,; 1234567890():,; 1234567890():,; light and interatomic dopant distances, which minimize optical losses and allow successful Nd doping. -
X-Ray Diffraction and Scanning Probe Microscopy
X-Ray Diffraction and Scanning Probe Microscopy X-Ray Diffraction Diffraction can occur when electromagnetic radiation interacts with a periodic structure whose repeat distance is about the same as the wavelength of the radiation. Visible light, for example, can be diffracted by a grating that contains scribed lines spaced only a few thousand angstroms apart, about the wavelength of visible light. X-rays have wavelengths on the order of angstroms, in the range of typical interatomic distances in crystalline solids. Therefore, X-rays can be diffracted from the repeating patterns of atoms that are characteristic of crystalline materials. Electromagnetic Properties of X-Rays The role of X-rays in diffraction experiments is based on the electromagnetic properties of this form of radiation. Electromagnetic radiation such as visible light and X-rays can sometimes behave as if the radiation were a beam of particles, while at other times it behaves as if it were a wave. If the energy emitted in the form of photons has a wavelength between 10-6 to 10-10 cm, then the energy is referred to as X-rays. Electromagnetic radiation can be regarded as a wave moving at the speed of light, c (~3 x 1010 cm/s in a vacuum), and having associated with it a wavelength, l , and a frequency, n, such that the relationship c = ln is satisfied. Gamma X-Rays Ultraviolet Visible Infrared Microwaves Radio rays rays light light Radar Waves Short Wavelength Long Wavelength High Frequency Low Frequency High Energy Low Energy V I B G Y O R 400 nm 700 nm Figure 1. -
Effects of Dopant Additions on the High Temperature Oxidation Behavior of Nickel-Based Alumina- Forming Alloys
Effects of Dopant Additions on the High Temperature Oxidation Behavior of Nickel-based Alumina- forming Alloys by Talia L. Barth A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy (Materials Science and Engineering) in the University of Michigan 2020 Doctoral Committee: Professor Emmanuelle Marquis, Chair Assistant Professor John Heron Professor Krishna Garikipati Professor Alan Taub Talia L. Barth [email protected] ORCID iD: 0000-0001-8266-7447 © Talia L. Barth 2020 ACKNOWLEDGEMENTS I would like to first offer my heartfelt thanks to my advisor, Professor Emmanuelle Marquis, without whom this work would not have been possible. Her exceptional mentorship has had an immense impact on my development as a researcher and a person, and her support and guidance along my journey have been invaluable. I would also like to express my appreciation for the rest of my committee, Professor Alan Taub, Assistant Professor John Heron, and Professor Krishna Garikipati for providing valuable advice and support for the completion of this work. I am grateful to the staff at the Michigan Center for Materials Characterization (MC)2, especially to Allen Hunter, Bobby Kerns, Haiping Sun, and Nancy Muyanja whose training enabled me to work confidently on the characterization instruments essential to this dissertation, and were always eager to lend their expertise with data collection and analysis. My colleagues in the Marquis group over the years were also important to this work and to my professional and personal development. I would like to thank Kevin Fisher, Ellen Solomon, Elaina Reese, and Peng-Wei Chu for getting me up to speed in the lab and for being there as mentors and friends in my first years as a grad student. -
Mapping the Unknown Atomic Force Microscopy and Other Scanning Probe Microscopy Techniques
Mapping the Unknown Atomic Force Microscopy and Other Scanning Probe Microscopy Techniques What it Atomic Force Microscopy and Scanning Probe Microscopy? Scanning Probe Microscopy is a general name for a set of techniques used to image atomic surfaces. With the help of Scanning Probe Microscopy technologies, scientists have been able to create images or “pictures” of atomic surfaces. With these technologies, we are able to “see” what atoms look like. There are a number of techniques. All of them employ some sort of probe that is run across the surface of a material to gather data. These probes usually measure some kind electrical and magnetic forces between the probe and atomic surface. This data is then used to create images of the surface. More in-depth information is contained in the Teacher Background section below. Unit Overview Imaging unknown surfaces is an important part of scientific research. It is often impossible or impractical to observe some surfaces directly. Surfaces of other planets, the ocean floor, and the atomic surfaces of objects must be observed and mapped indirectly. Accurate data gathering and the use of computers to put the data into a visual image are explored in this activity. In this activity, students gather data about an unknown surface inside a shoebox, record the data, and transform the data into 2D and 3D models of the unknown surface. If Microsoft Excel is available, students may also enter the data into a spreadsheet and create a 3D image. Remote imaging has long been used in the study of the ocean floor. Early in the history of oceanography, scientists would drop very long cables with weights attached to the end of the cable to the bottom of the ocean. -
Fabrication of Sharp Atomic Force Microscope Probes Using In-Situ Local Electric Field Induced Deposition Under Ambient Conditions
The following article has been accepted by Review of Scientific Instruments (RSI). After it is published, it will be found at http://scitation.aip.org/content/aip/journal/rsi Fabrication of sharp atomic force microscope probes using in-situ local electric field induced deposition under ambient conditions Alexei Temiryazev1, a), Sergey I. Bozhko2, A. Edward Robinson3, and Marina Temiryazeva1 1Kotel’nikov Institute of Radioengineering and Electronics of RAS, Fryazino Branch, 141190 Fryazino, Russia 2Institute of Solid State Physics, RAS, 142432 Chernogolovka, Russia 3AIST-NT Inc. 359 Bel Marin Keys Blvd., Suite 20 Novato, CA 94949, USA We demonstrate a simple method to significantly improve the sharpness of standard silicon probes for an atomic force microscope, or to repair a damaged probe. The method is based on creating and maintaining a strong, spatially localized electric field in the air gap between the probe tip and the surface of conductive sample. Under these conditions, nanostructure growth takes place on both the sample and the tip. The most likely mechanism is the decomposition of atmospheric adsorbate with subsequent deposition of carbon structures. This makes it possible to grow a spike of a few hundred nanometers in length on the tip. We further demonstrate that probes obtained by this method can be used for high-resolution scanning. It is important to note that all process operations are carried out in-situ, in air and do not require the use of closed chambers or any additional equipment beyond the atomic force microscope itself. I. INTRODUCTION Currently, the vast majority of measurements made with atomic force microscopes, are carried out using silicon probes. -
Segmented Solid State Laser Gain Media with Gradient
Europaisches Patentamt (19) European Patent Office Office europeenpeen des brevets EP 0 655 170 B1 (12) EUROPEAN PATENT SPECIFICATION (45) Date of publication and mention (51) intci.6: H01S 3/07, H01S 3/094, of the grant of the patent: H01S3/16 18.12.1996 Bulletin 1996/51 (86) International application number: (21) Application number: 93918690.4 PCT/US93/07423 Date of 05.08.1993 (22) filing: (87) International publication number: WO 94/05062 (03.03.1994 Gazette 1994/06) (54) SEGMENTED SOLID STATE LASER GAIN MEDIA WITH GRADIENT DOPING LEVEL SEGMENTIERTES VERSTAERKUNGSMEDIUM FUER FESTKOERPERLASER MIT GRADIENTENFOERMIGER DOTIERUNGSSTAERKE MILIEUX DE GAIN SEGMENTES A LASER A SOLIDE PRESENTANT UN NIVEAU DE DOPAGE A GRADIENT (84) Designated Contracting States: • SHAND, Michael, L. FR Morristown, NJ 07962 (US) (30) Priority: 17.08.1992 US 930256 (74) Representative: Hucker, Charlotte Jane et al Gill Jennings & Every (43) Date of publication of application: Broadgate House, 31.05.1995 Bulletin 1995/22 7 Eldon Street London EC2M 7LH (GB) (73) Proprietor: AlliedSignal Inc. Morristown, New Jersey 07962-2245 (US) (56) References cited: EP-A- 0 454 865 US-A-3 626 318 (72) Inventors: US-A- 4 860 301 US-A- 5 105 434 • RAPOPORT, William, R. Bridgewater, NJ 08807 (US) DO o lO CO Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice the Patent Office of the Notice of shall be filed in o to European opposition to European patent granted. opposition a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. -
Creating and Probing Electron Whispering-Gallery Modes in Graphene
Creating and probing electron whispering-gallery modes in graphene The MIT Faculty has made this article openly available. Please share how this access benefits you. Your story matters. Citation Zhao, Y., J. Wyrick, F. D. Natterer, J. F. Rodriguez-Nieva, C. Lewandowski, K. Watanabe, T. Taniguchi, L. S. Levitov, N. B. Zhitenev, and J. A. Stroscio. “Creating and Probing Electron Whispering-Gallery Modes in Graphene.” Science 348, no. 6235 (May 7, 2015): 672–675. As Published http://dx.doi.org/10.1126/science.aaa7469 Publisher American Association for the Advancement of Science (AAAS) Version Author's final manuscript Citable link http://hdl.handle.net/1721.1/96969 Terms of Use Creative Commons Attribution-Noncommercial-Share Alike Detailed Terms http://creativecommons.org/licenses/by-nc-sa/4.0/ Creating and Probing Electron Whispering Gallery Modes in Graphene Yue Zhao1, 2*, Jonathan Wyrick1*, Fabian D. Natterer1*, Joaquin Rodriguez Nieva3*, Cyprian Lewandowski4, Kenji Watanabe5, Takashi Taniguchi5, Leonid Levitov3, Nikolai B. Zhitenev1†, and Joseph A. Stroscio1† 1Center for Nanoscale Science and Technology, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA 2Maryland NanoCenter, University of Maryland, College Park, MD 20742, USA 3Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA 4Department of Physics, Imperial College London, London SW7 2AZ, UK 5National Institute for Materials Science, Tsukuba, Ibaraki 305-0044, JAPAN *These authors contributed equally to this work †Corresponding authors. E-mail: [email protected], [email protected] Abstract: Designing high-finesse resonant cavities for electronic waves faces challenges due to short electron coherence lengths in solids. Previous approaches, e.g.