DOCSLIB.ORG

Physics and Material Science of Semiconductor Nanostructures

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Physics and Material Science of Semiconductor Nanostructures Physics and Material Science of Semiconductor Nanostructures PHYS 570P Prof. Oana Malis Email: [email protected] Course website: http://www.physics.purdue.edu/academic_programs/courses/phys570P/ Today Bulk semiconductor growth • Single‐crystal techniques Nanostructure fabrication • Epitaxial growth MBE Ref. Ihn Chapter 2 Types of Crystalline Semiconductors: Silicon • Different levels of crystal structure may exist ranging from single crystal to totally non-crystalline – Single crystal silicon – Multi-crystal silicon – Polycrystalline – Ribbon silicon – Amorphous silicon • The main difference between each is the crystal grain size and their growth technique Different Forms of Silicon Crystal Type Symbol Crystal Grain Common Growth Size Techniques Single-crystal sc-Si > 10 cm Czochralski (Cz), Float-Zone (FZ) Multicrystalline mc-Si 10cm Cast, Spheral, Sheet, ribbon Polycrystalline pc-Si 1m – 1mm Evaporation , CVD, sputtering Crystal growth Process flow from starting material to polished wafer. Semiconductor-Grade Silicon Steps to Obtaining Semiconductor Grade Silicon (SGS) Step Description of Process Reaction Reduction of silica: produce metallurgical grade silicon 1 SiC (s) + SiO (s) Si (l) + SiO(g) + CO (g) (MGS) by heating silica with 2 carbon (97% pure) Purify MG silicon through a chemical reaction to produce a silicon-bearing gas of 2 Si (s) + 3HCl (g) SiHCl3 (g) + H2 (g) + heat trichlorosilane (SiHCl3) Additional purification via distillation CVD: SiHCl3 and hydrogen react in a process called 3 Siemens to obtain pure 2SiHCl3 (g) + 2H2 (g) 2Si (s) + 6HCl (g) semiconductor- grade silicon (SGS) Single Crystal Growth Techniques • Czochralski Growth (Cz) – Most single crystal silicon made this way – Lower quality silicon than FZ with Carbon and Oxygen present – Cheaper production than FZ – Produces cylinders and circular wafers • Float Zone (FZ) – Better Quality than Cz – More Expensive than Cz – Produces cylinders and circular wafers Czochralski Method • Pure Silicon is melted in a quartz crucible under vacuum or inert gas and a seed crystal is dipped into the melt • The seed crystal is slowly withdrawn and slowly rotated so that the molten silicon crystallizes to the seed (Rock Candy) • The melt temperature, rotation rate and pull rate are controlled to create a ingot of a certain diameter Modern CZ Crystal Growth • The raw Si used for crystal growth is purified from SiO2 (sand) through refining, fractional distillation and CVD. • The raw material contains < 0.01 ppb impurities except for O ( 1018 cm-3) and C ( 1016 cm-3) • Essentially all Si wafers used for ICs today come from Czochralski grown crystals. • Polysilicon material is melted, held at close to 1415 °C, and a single crystal seed is used to start the crystal growth. • Pull rate, melt temperature and rotation rate are all important control parameters. Czochralski Technique Spinning rod with “Seed” Crystal lowered into the molten silicon Slowly pulled up to allow silicon to crystallize on the seed layer Molten Silicon Once to the size desired, the crystal is pulled faster to maintain the needed diameter CZ crystal growth (cont.) • Sequence of photographs and drawings illustrating CZ crystal growth. The charge is melted, • the seed is inserted, the neck region is grown at a high rate to remove dislocations and finally the growth is • slowed down to produce a uniform crystal. Czochralski Growth • Entire ingots of silicon produced as one big crystal • Very high quality material with few defects • No boundaries between crystals because it is one crystal in one orientation • Si crystal inevitably contains oxygen impurities dissolved from the quartz crucible holding the molten silicon 13 12” (30 cm) Boule Drawback of the CZ method • The only significant drawback to the CZ method is that the silicon is contained in liquid form in a crucible during growth and as a result, impurities from the crucible are incorporated • in the growing crystal. Oxygen and carbon are the two most significant contaminants. • These impurities are not always a drawback, however. Oxygen in particular can be very useful in mechanically strengthening the silicon crystal and in providing a means for gettering other unwanted impurities during device fabrication. Lacture # 3 15 Float Zone Method • Produced by cylindrical polysilicon rod that already has a seed crystal in its lower end • An encircling inductive heating coil melts the silicon material • The coil heater starts from the bottom and is raised pulling up the molten zone • A solidified single crystal ingot forms below • Impurities prefer to remain in the molten silicon so very few defects and impurities remain in the forming crystal Dopant Concentration Nomenclature Concentration (Atoms/cm3) Material 14 14 16 16 19 19 Dopant < 10 10 to 10 10 to 10 >10 Type (Very Lightly Doped) (Lightly Doped) (Doped) (Heavily Doped) -- - + Pentavalent n n n n n -- - + Trivalent p p p p p Basic Process Steps for Wafer Preparation Wafer Lapping Crystal Growth and Edge Grind Cleaning Shaping Etching Inspection Wafer Slicing Polishing Packaging Slicing into Wafers • Ingots are cut into thin wafers • Two Techniques – Wire sawing – Diamond blade sawing • Both results in loss of silicon from “kerf losses” silicon saw dust • Time consuming • Water Cooled, Dirty Ingot Diameter Grind Preparing crystal ingot for grinding Internal diameter wafer saw Diameter grind Flat grind Wafer Polishing: single or double side Upper polishing pad Wafer Slurry Lower polishing pad Wafer Notch and Laser Scribe Notch Scribed identification number Chemical Etch of Wafer Surface to Remove Sawing Damage Silicon Wafer Fabrication Review • Raw materials (SiO2) are refined to produce electronic grade silicon with a purity unmatched by any other available material on earth. • CZ crystal growth produces structurally perfect Si single crystals which are cut into wafers and polished. • Starting wafers contain only dopants, and trace amounts of contaminants O and C in measurable quantities. • Dopants can be incorporated during crystal growth • Point, line, and volume (1D, 2D, and 3D) defects can be present in crystals, particularly after high temperature processing. • Point defects are "fundamental" and their concentration depends on temperature (exponentially), on doping level and on other processes like ion implantation which can create non-equilibrium transient concentrations of these defects. Nanostructure fabrication Top-down versus bottom up: An analogy If we want to make a very small tree we can either… Get a very big piece of wood Plant a seed and then control and carve it into a much its growth to form a fully- smaller model tree functioning bonsai tree (TOP DOWN APPROACH) (BOTTOM UP APPROACH) Epitaxy The wafers grown through the described bulk techniques are rarely used in direct device manufacture, but are used as substrates instead. Solution: grow one or more layers (of some <m thickness) over them. The epitaxial growth techniques have low growth rate (as low as one single layer per second in some techniques) which allows a high precision size control in the growth direction, which is essential for the heterostructure variety that is nowadays used in devices. Epitaxy The extended growth of single-crystal films on single-crystal substrates Characterised by a well defined crystal orientation relationship between the film (A) and the substrate (B), e.g. (for cubic materials): (110)A//(110)B [001]A//[001]B Homoepitaxy: Heteroepitaxy: - Same film and substrate - Different film and substrate - Essentially no lattice materials mismatch - Significant lattice mismatch - Material properties - Material properties affected by unaffected biaxial strain Molecular Beam Epitaxy MBE Molecular beam epitaxy • Thin film growth in high vacuum or ultra high vacuum (10−8 Pa). – Deposition rates are typically slow (less than 1000 nm per hour) so high vacuum is required to achieve high purity material. • Ultra-pure elements (e.g. gallium and arsenic) are heated in separate crucibles until they begin to slowly sublimate. • The gaseous elements then condense on the substrate, where they may react with each other (e.g. Ga + As GaAs). • The term “molecular beam" implies that the evaporated atoms do not interact with each other or vacuum chamber gases until they reach the substrate. Effusion cells Basic schematic Real example Temperature control is very important since small temperature controls equilibrium vapour pressure, aperture and hence deposition rate solid close to equilibrium with gas Shutter over aperture – must operate very quickly to ensure fast switching between beams of different Heat elements (e.g. In, Ga) and achieve sharp interfaces. Monitoring MBE: RHEED Reflection high-energy electron diffraction • Same high-vacuum requirements as for molecular beams. • Electron beam interacts with surface layers at glancing angle • Elastically scattered electrons form streaks on screen if surface is flat GaAs (110) surface RHEED: growth modes and surface reconstructions Growth modes: 2D growth: step flow 2D growth: layer-by-layer (Frank-van der Merwe) 3D growth: layer-plus-island (Stranski-Krastanov) 3D growth: island (Volmer-Weber) RHEED: layer-by-layer growth • Intensity oscillations of RHEED streaks can be used to find the growth rate • Slow growth rates enable monolayer-by-monolayer growth. • Complete monolayer smooth surface peak in RHEED intensity • Partial monolayer rougher surface reduced RHEED intensity • One period of RHEED oscillation gives time for growth of one monolayer. RHEED: 3D
Load more

Recommended publications
  • Deformation and Recrystallization of Single Crystal Nickel-Based
    Journal of Materials Processing Technology 217 (2015) 1–12 Contents lists available at ScienceDirect Journal of Materials Processing Technology jo urnal homepage: www.elsevier.com/locate/jmatprotec Deformation and recrystallization of single crystal nickel-based superalloys during investment casting a b a,∗ b a Li Zhonglin , Xiong Jichun , Xu Qingyan , Li Jiarong , Liu Baicheng a School of Materials Science and Engineering, Key Laboratory for Advanced Materials Processing Technology, Ministry of Education, Tsinghua University, Beijing 100084, China b National Key Laboratory of Advanced High Temperature Structural Materials, Beijing Institute of Aeronautical Materials, Beijing 100095, China a r t i c l e i n f o a b s t r a c t Article history: A semi-quantitative, macroscopic, phenomenon-based, thermo-elastic–plastic model was developed to Received 28 August 2014 predict the final plastic strains of single crystal nickel-based superalloys by considering their orthotropic Received in revised form 21 October 2014 mechanical properties. Various cases were considered and simulated to investigate the basic factors Accepted 23 October 2014 that influence the final plasticity. Thermo-mechanical numerical analysis was conducted to predict the Available online 4 November 2014 recrystallization sites of simplified cored rods, with the results in good agreement with the experimental results. These hollowed rods with thin walls showed an increased propensity for recrystallization. The Keywords: geometric features, especially stress concentration sites, are more significant to the induced plasticity Single crystal Superalloys than the material’s orientation or shell/core materials. This paper also attempts to provide useful sug- gestions, such as introducing filets, to avoid causing plastic strains during the casting process that induce Investment casting Plastic deformation recrystallization.
    [Show full text]
  • The Forsterite-Anorthite-Albite System at 5 Kb Pressure Kristen Rahilly
    The Forsterite-Anorthite-Albite System at 5 kb Pressure Kristen Rahilly Submitted to the Department of Geosciences of Smith College in partial fulfillment of the requirements for the degree of Bachelor of Arts John B. Brady, Honors Project Advisor Acknowledgements First I would like to thank my advisor John Brady, who patiently taught me all of the experimental techniques for this project. His dedication to advising me through this thesis and throughout my years at Smith has made me strive to be a better geologist. I would like to thank Tony Morse at the University of Massachusetts at Amherst for providing all of the feldspar samples and for his advice on this project. Thank you also to Michael Jercinovic over at UMass for his help with last-minute carbon coating. This project had a number of facets and I got assistance from many different departments at Smith. A big thank you to Greg Young and Dale Renfrow in the Center for Design and Fabrication for patiently helping me prepare and repair the materials needed for experiments. I’m also grateful to Dick Briggs and Judith Wopereis in the Biology Department for all of their help with the SEM and carbon coater. Also, the Engineering Department kindly lent their copy of LabView software for this project. I appreciated the advice from Mike Vollinger within the Geosciences Department as well as his dedication to driving my last three samples over to UMass to be carbon coated. The Smith Tomlinson Fund provided financial support. Finally, I need to thank my family for their support and encouragement as well as my friends here at Smith for keeping this year fun and for keeping me balanced.
    [Show full text]
  • 21St American Conference on Crystal Growth and Epitaxy (ACCGE-21)
    Program Book 21st American Conference on Crystal Growth and Epitaxy (ACCGE-21) and 18th US Workshop on Organometallic Vapor Phase Epitaxy (OMVPE-18) and 3rd Symposium on 2D Electronic Materials and Symposium on Epitaxy of Complex Oxides July 30 – August 4 1 | P a g e Table of Contents Table of Contents ........................................................................................................... 2 Welcome to Santa Fe, New Mexico………………………………...………………………..3 Maps of Conference Area and Resort ............................................................................ 4 Conference Sponsors & Supporters ............................................................................... 7 Conference Exhibitors .................................................................................................... 7 Conference Organizers .................................................................................................. 8 OMVPE Workshop Committee………………………. ...................................................... 9 AACG Organization (2015-2017) ................................................................................. 10 ACCGE Symposia and Organizers .................................................... ………………….11 Plenary Speakers ............................................................................... ………………….13 Award Recipients ............................................................................... ………………….14 Scope and Purpose of the Conferences ......................................................................
    [Show full text]
  • Growth and Characterization of Lif Single-Crystal Fibers by the Micro
    ARTICLE IN PRESS Journal of Crystal Growth 270 (2004) 121–123 Growth and characterization of LiF single-crystal fibers by the micro-pulling-down method A.M.E. Santoa, B.M. Epelbaumb, S.P. Moratoc, N.D. Vieira Jr.a, S.L. Baldochia,* a Instituto de Pesquisas Energeticas! e Nucleares, IPEN-CNEN/SP, Av. Prof. Lineu Prestes, CEP 05508-900, Sao* Paulo, SP, Brazil b Department of Materials Science, University of Erlangen-Nurnberg, D-91058, Erlangen, Germany c LaserTools Tecnologia Ltda., 05379-130,Sao* Paulo, SP, Brazil Accepted 27 May 2004 Available online 20 July 2004 Communicated by G. Muller. Abstract Good optical quality LiF single-crystalline fibers ranging from 0:5to0:8 mm in diameter and 100 mm in length were successfully grown by the micro-pulling-down technique in the resistive mode. A commercial equipment was modified in order to achieve suitable conditions to grow fluoride single-crystalline fibers. r 2004 Elsevier B.V. All rights reserved. PACS: 81.10.Fq; 78.20.Àe Keywords: A2. Micro-pulling-down method; A2. Single crystal growth; B1. Fluorides 1. Introduction oxide single-crystals have already been grown by the laser heated pedestal growth (LHPG) [2] and There is an increasinginterest in the production by the micro-pulling-down (m-PD) [3] methods. of single-crystalline fibers. Their unique properties However, the growth and hence the possible indicate their use for production of a variety of applications of fluoride single-crystalline fibers optical and electronic devices [1]. The final shape has not yet been investigated. of the single-crystalline fiber is already in a form As it is already known from other methods of suitable for optical testingand applications, fluoride growth, these materials are very sensitive reducingthe time and cost of preparation.
    [Show full text]
  • Advances in Photovoltaics: Part 3 SERIES EDITORS
    VOLUME NINETY SEMICONDUCTORS AND SEMIMETALS Advances in Photovoltaics: Part 3 SERIES EDITORS EICKE R. WEBER Director Fraunhofer-Institut fur€ Solare Energiesysteme ISE Vorsitzender, Fraunhofer-Allianz Energie Heidenhofstr. 2, 79110 Freiburg, Germany CHENNUPATI JAGADISH Australian Laureate Fellow and Distinguished Professor Department of Electronic Materials Engineering Research School of Physics and Engineering Australian National University Canberra, ACT 0200 Australia VOLUME NINETY SEMICONDUCTORS AND SEMIMETALS Advances in Photovoltaics: Part 3 Edited by GERHARD P. WILLEKE Fraunhofer Institute for Solar Energy Systems ISE, Freiburg, Germany EICKE R. WEBER Fraunhofer Institute for Solar Energy Systems ISE, Freiburg, Germany AMSTERDAM • BOSTON • HEIDELBERG • LONDON NEW YORK • OXFORD • PARIS • SAN DIEGO SAN FRANCISCO • SINGAPORE • SYDNEY • TOKYO Academic Press is an imprint of Elsevier Academic Press is an imprint of Elsevier 32 Jamestown Road, London NW1 7BY, UK 525 B Street, Suite 1800, San Diego, CA 92101-4495, USA 225 Wyman Street, Waltham, MA 02451, USA The Boulevard, Langford Lane, Kidlington, Oxford OX5 1GB, UK First edition 2014 Copyright © 2014 Elsevier Inc. All rights reserved No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or any information storage and retrieval system, without permission in writing from the publisher. Details on how to seek permission, further information about the Publisher’s permissions policies and our arrangements with organizations such as the Copyright Clearance Center and the Copyright Licensing Agency, can be found at our website: www.elsevier.com/permissions. This book and the individual contributions contained in it are protected under copyright by the Publisher (other than as may be noted herein).
    [Show full text]
  • Single Crystals from Metal Solutions
    Single Crystals from Metal Solutions centration of less than about 5 percent (the limit we had established by x-ray diffraction iven a free choice, any solid-state experimentalist would characterize a techniques) would produce some increase, material by making measurements on a single crystal rather than a depending on its concentration. but the in- G polycrystalline sample. A single crystal more accurately represents the crease would be nowhere near that expected material (since it is free of grain boundaries at which impurities can hide) and is in fact if UPt3 itself was a superconductor. (The required for measuring the directional dependence of various properties. Yet growing BCS theory predicts an increase of about 150 a single crystal can be exceptionally difficult, and a large number of important percent.) experiments await the preparation of appropriate single crystals. The whiskers we could gather at the time Numerous techniques exist for growing crystals, but finding one that works for a for the specific heat measurement amounted particular material can be frustrating and time-consuming. A method we use quite to only 20 milligrams, but, fortunately. we often in our research is growth from slowly cooled solutions of the desired materiaI in have developed techniques and equipment for a molten metallic solvent, (This method is an easy extension of the observed natural measuring specific heats of very small sam- growth of single crystals from aqueous solutions.) We have used as solvents such ples. We spent nine days hovering over the metals as aluminum, iridium, tin, copper, bismuth, and gallium, The solvent provides a refrigerator, and by Friday.
    [Show full text]
  • Growth of Srb4o7 Crystal Fibers Along the C-Axis by Micro-Pulling-Down Method
    crystals Article Growth of SrB4O7 Crystal Fibers along the c-Axis by Micro-Pulling-Down Method Ryouta Ishibashi, Harutoshi Asakawa * and Ryuichi Komatsu Graduate School of Science and Engineering, Yamaguchi University, Yamaguchi 753-8511, Japan; [email protected] (R.I.); [email protected] (R.K.) * Correspondence: [email protected]; Tel.: +81-836-85-9631 Abstract: SrB4O7 (SBO) receives much attention as solid-state ultraviolet lasers for micro-machining, photochemical synthesis, and laser spectroscopy. For the application of SBO, the SBO crystals require the control of twinning to amplify the conversion light. We also expected that the inhibitation of the SrB2O4 appearance was essential. Here, we show the growth of SBO crystals along the c-axis through the micro-pulling-down method while alternating the application of electric fields (E). Without the application, single crystals were grown. At E = 400 V/cm no needle domains of SrB2O4 inside SBO crystals existed; however, composition planes were formed and twin boundaries did not appear. In contrast, the inversion of surface morphology emerged, and the convex size was especially large at 1000 V/cm. These results demonstrate that convection is generated perpendicular to the growth front by alternating the application of electric fields. This surface morphological change contradicts the conventional concept of growth through the micro-pulling-down method. The distance from seed crystals vs. grain density plot also showed that the density did not decrease with a sufficient slope. Consequently, we concluded that the selection of the c-axis as growth faces is not fruitful to fabricate Citation: Ishibashi, R.; Asakawa, H.; twins, and the selection of the growth condition, under which geometrical selection strongly affects, Komatsu, R.
    [Show full text]
  • PV) Technologies
    Australian Journal of Basic and Applied Sciences, 8(6) April 2014, Pages: 455-468 AENSI Journals Australian Journal of Basic and Applied Sciences ISSN:1991-8178 Journal home page: www.ajbasweb.com Current State-of-the-Art Solar Photovoltaic (PV) Technologies Banupriya Balasubramanian and A. Mohd Ariffin Center of Renewable Energy (CRE), Universiti Tenaga Nasional (UNITEN), Jalan IKRAM – UNITEN, Kajang, Selangor, Malaysia ARTICLE INFO ABSTRACT Article history: One of the most rapidly emerging renewable energy technologies is solar photovoltaic Received 25 January 2014 (SPV) cell. SPV cell is a specialized semiconductor device that converts visible light or Received in revised form 12 light energy directly into useful electrical energy. This paper work aims to provide a March 2014 comprehensive overview on the current state-of-the-art solar PV technologies. Each Accepted 14 April 2014 technology is reviewed in detail particularly on its use of light absorbing materials Available online 25 April 2014 together with its structure and deposition processes. Furthermore, conversion efficiency, advantages and disadvantages of these technologies are also discussed. This Keywords: comprehensive review is hoped encourage more participation from various parties in Solar PV technologies, Review, SPV, advancing the use of SPV as an alternative to generate electricity. Silicon, Thin film © 2014 AENSI Publisher All rights reserved. To Cite This Article: Banupriya Balasubramanian and A. Mohd Ariffin., Current State-of-the-Art Solar Photovoltaic (PV) Technologies. Aust. J. Basic & Appl. Sci., 8(6): 455-468, 2014 INTRODUCTION Renewable energy is a naturally available energy that replenishes rapidly for instance solar, wind, hydro and biomass. Solar energy is a form of renewable energy that has zero carbon emission and can be produced almost at any time, as long as sunlight is present.
    [Show full text]
  • Epitaxy and Characterization of Sigec Layers Grown by Reduced Pressure Chemical Vapor Deposition
    Epitaxy and characterization of SiGeC layers grown by reduced pressure chemical vapor deposition Licentiate Thesis by Julius Hållstedt Stockholm, Sweden 2004 Laboratory of Semiconductor materials, Department of Microelectronics and Information Technology (IMIT), Royal Institute of Technology (KTH) Epitaxy and characterization of SiGeC layers grown by reduced pressure chemical vapor deposition A dissertation submitted to the Royal Institute of Technology, Stockholm, Sweden, in partial fulfillment of the requirements for the degree of Teknologie Licentiat. TRITA-HMA REPORT 2004:1 ISSN 1404-0379 ISRN KTH/HMA/FR-04/1-SE © Julius Hållstedt, March 2004 This thesis is available in electronic version at: http://media.lib.kth.se Printed by Universitetsservice US AB, Stockholm 2004 ii Julius Hållstedt Epitaxy and characterization of SiGeC layers grown by reduced pressure chemical vapor deposition Laboratory of Semiconductor Materials (HMA), Department of Microelectronics and Information Technology (IMIT), Royal Institute of Technology (KTH), Stockholm, Sweden TRITA-HMA Report 2004:1, ISSN 1404-0379, ISRN KTH/HMA/FR-04/1-SE Abstract Heteroepitaxial SiGeC layers have attracted immense attention as a material for high frequency devices during recent years. The unique properties of integrating carbon in SiGe are the additional freedom for strain and bandgap engineering as well as allowing more aggressive device design due to the potential for increased thermal budget during processing. This work presents different issues on epitaxial growth, defect density, dopant incorporation and electrical properties of SiGeC epitaxial layers, intended for various device applications. Non-selective and selective epitaxial growth of Si1-x-yGexCy (0≤x≤0.30, 0≤y≤0.02) layers have been optimized by using high-resolution x-ray reciprocal lattice mapping.
    [Show full text]
  • An Investigation of the Techniques and Advantages of Crystal Growth
    Int. J. Thin. Film. Sci. Tec. 9, No. 1, 27-30 (2020) 27 International Journal of Thin Films Science and Technology http://dx.doi.org/10.18576/ijtfst/090104 An Investigation of the Techniques and Advantages of Crystal Growth Maryam Kiani*, Ehsan Parsyanpour and Feridoun Samavat* Department of Physics, Bu-Ali Sina University, Hamadan, Iran. Received: 2 Aug. 2019, Revised: 22 Nov. 2019, Accepted: 23 Nov. 2019 Published online: 1 Jan. 2020 Abstract: An ideal crystal is built with regular and unlimited recurring of crystal unit in the space. Crystal growth is defined as the phase shift control. Regarding the diverse crystals and the need to produce crystals of high optical quality, several many methods have been proposed for crystal growth. Crystal growth of any specific matter requires careful and proper selection of growth method. Based on material properties, the considered quality and size of crystal, its growth methods can be classified as follows: solid phase crystal growth process, liquid phase crystal growth process which involves two major sub-groups: growth from the melt and growth from solution, as well as vapour phase crystal growth process. Methods of growth from solution are very important. Thus, most materials grow using these methods. Methods of crystal growth from melt are those of Czochralski (tensile), the Kyropoulos, Bridgman-Stockbarger, and zone melting. In growth of oxide crystals with good laser quality, Czochralski method is still predominant and it is widely used in the production of most solid-phase laser materials. Keywords: Crystal growth; Czochralski method; Kyropoulos method; Bridgman-Stockbarger method. A special method is used for each group of elements depending on their usage and importance of their impurity, or consideration of form, impurity and size of crystal.
    [Show full text]
  • Single-Crystal Metal Growth on Amorphous Insulating Substrates
    Single-crystal metal growth on amorphous insulating substrates Kai Zhanga,1, Xue Bai Pitnera,1, Rui Yanga, William D. Nixb,2, James D. Plummera, and Jonathan A. Fana,2 aDepartment of Electrical Engineering, Stanford University, Stanford, CA 94305; and bDepartment of Materials Science and Engineering, Stanford University, Stanford, CA 94305 Contributed by William D. Nix, December 1, 2017 (sent for review October 12, 2017; reviewed by Hanchen Huang, David J. Srolovitz, and Carl Thompson) Metal structures on insulators are essential components in advanced Our method is based on liquid phase epitaxy, in which the electronic and nanooptical systems. Their electronic and optical polycrystalline metal structures are encapsulated in an amor- properties are closely tied to their crystal quality, due to the strong phous insulating crucible, together with polycrystalline seed dependence of carrier transport and band structure on defects and structures of differing material, and heated to the liquid phase. grain boundaries. Here we report a method for creating patterned As the system cools, the metal solidifies into single crystals. single-crystal metal microstructures on amorphous insulating sub- Liquid phase epitaxy has been previously studied in the context of strates, using liquid phase epitaxy. In this process, the patterned semiconductor-on-oxide growth (24–26), but has not been ex- metal microstructures are encapsulated in an insulating crucible, plored for metal growth. We will examine gold as a model system together with a small seed of a differing material. The system is in this study. Gold is an essential material in electronics and heated to temperatures above the metal melting point, followed by plasmonics because of its high conductivity and chemical inertness.
    [Show full text]
  • 3 Single Crystals Using Czochralski Method
    Journal of Siberian Federal University. Engineering & Technologies 4 (2009 2) 400-408 ~ ~ ~ УДК 669:621.315.592 Synthesis of Ca4GdO(BO3)3 Single Crystals using Czochralski Method Robert Möckel*, Margitta Hengst, Christoph Reuther and Jens Götze TU Bergakademie Freiberg, Institute of Mineralogy, Brennhausgasse 14, D-09596 Freiberg, Germany 1 Received 16.11.2009, received in revised form 03.12.2009, accepted 18.12.2009 The oxoborate Ca4GdO(BO3)3 (GdCOB) is a potential material for advanced industrial applications because of its optical and electric properties. High quality single crystals of GdCOB have been grown from a melt using the Czochralski method. Single crystals of laboratory scale are of good optical quality showing no macroscopic defects like cracks, inclusions or discolouration. Crystals in [001] direction reveal regular growth, whereas crystals in [010] are of asymmetric shape but show less difficulties during the growth process. Keywords: single crystal growth, Czochralski, oxoborate, Ca4GdO(BO3)3. 1. Introduction First investigations on the system REE2O3–CaO–B2O3 go back to the late 1960s, early 1970s, when Kindermann took care of the whole system [1]. Most of these early syntheses were realized by solid state reactions. Later, Ca4REEO(BO3)3 (REECOB) was synthesized and described by Norrestam & Nygren [2], who produced the materials by simple solid state reactions of stoichiometric mixtures as well. They showed that most trivalent REE like La, Nd, Sm, Gd, Er, and Y fit into the crystal lattice crystallizing isostructurally. First analysis of the crystallographic structures revealed analogies to calcium fluoroborate (Ca5F(BO3)3) and also to well known structure of common fluorapatite (Ca5[F/(PO4)3]).
    [Show full text]