Nanoscale Quantification Of Stress And Strain In Iii V Semiconducting Nanostructures

III-V semiconducting nanostructures present a promising platform for the realization of advanced optoelectronic devices due to their superior intrinsic materials properties including direct band gap energies that span the visible light spectrum and high carrier mobilities. Additionally, the inherently high surface-to-volume ratio of nanostructures allows for the efficient relaxation of stress enabling the realization of defect free heterostructures between highly mismatched materials. As a result, nanostructures are being investigated as a route towards the direct integration of III-V materials on silicon substrates and as platforms for the fabrication of novel heterostructures not achievable in a thin film geometry. Due to their small size, however, many of the methods used to calculate stress and strain in 2D bulk systems are no longer valid as free surface effects allow for relaxation creating more complicated stress and strain fields. These inhomogeneous strain fields could have significant impacts on both device fabrication and operation. Therefore, it will be vital to develop techniques that can accurately predict and measure the stress and strain in individual nanostructures. In this thesis, we demonstrate how the combination of advanced transmission electron microscopy (TEM) and continuum modeling techniques can provide a quantitative understanding of the complex strain fields in nanostructures with high spatial resolutions. Using techniques such as convergent beam electron diffraction, nanobeam electron diffraction, and geometric phase analysis we quantify and map the strain fields in top-down fabricated InAlN/GaN high electron mobility transistor structures and GaAs/GaAsP core-shell nanowires grown by a particle-mediated vapor-liquid-solid mechanism. By comparing our experimental results to strain fields calculated by finite element analysis, we show that these techniques can provide quantitative strain information with spatial resolutions on the order of 1 nm. Our results highlight the importance of nanoscale characterization of strain in nanostructures and point to future opportunities for strain engineering to precisely tune the behavior and operation of these highly relevant structures.

Based on 3D process and device simulations with mechanical stress simulations by finite element techniques, this book explains performance assessment of nanoscale devices with strained SiGe and other stressors. It explains the process-induced stress transfer and developments at 7nm technology and below node in the area of strain-engineered devices.

The incorporation of rare earth-V (RE-V) semimetallic nanoparticles embedded in III-V compound semiconductors is of great interest for applications in solid-state devices including multijunction tandem solar cells, thermoelectric devices, and fast photoconductors for terahertz radiation sources and receivers. With regard to those nanoparticle roles in device applications and material itself, electrical and thermal properties of embedded RE-V nanoparticles, including nanoscale morphology, electronic structure, and electrical and thermal conductivity of such nanoparticles are essential to be understood to engineer their properties to optimize their influence on device performance. To understand embedded RE-V semimetallic nanostructures in III-V compound semiconductors, nanoscale characterization tools are essential for analysis their properties incorporated in compound semiconductors. In this dissertation, we used atomic force microscopy (AFM) with other secondary detection tools to investigate nanoscale material properties of semimetallic RE-V and GaAs heterostructures, grown by molecular beam epitaxy. We used scanning capacitance microscopy and conductive AFM techniques to understand electronic and electrical properties of ErAs/GaAs heterostructures. For the electrical properties, this thesis investigates details of statistical analysis of scanning capacitance and local conductivity images contrast to provide insights into (i) nanoparticle structure at length scales smaller than the nominal spatial resolution of the scanned probe measurement, and (ii) both lateral and vertical nanoparticle morphology at nanometer to atomic length scales, and their influence on electrical conductivity. To understand thermal properties of ErAs nanoparticles, in-plane and cross-sectional plane of ErAs/GaAs superlattice structure were investigated with a scanning probe microscopy technique implemented with 3[omega] method for thermal measurement. By performing detailed numerical modeling of thermal transport between thermal probe tip and employed samples, and estimation of additional phonon scattering induced by ErAs nanoparticles, we could understand influences of ErAs nanoparticles on the host GaAs thermal conductivity. Investigation of ErAs semimetallic nanostructure embedded in GaAs matrix with scanned probe microscopy provided detailed understanding of their electronic, electrical and thermal properties. In addition, this dissertation also demonstrates that an atomic force microscope with secondary detection techniques is promising apparatus to understand and investigate intrinsic properties of nanostructure materials, nanoscale charge transports, when the system is combined with detailed modeling and simulations.

Bringing together experts from the various disciplines involved, this first comprehensive overview of the current level of stress engineering on the nanoscale is unique in combining the theoretical fundamentals with simulation methods, model systems and characterization techniques. Essential reading for researchers in microelectronics, optoelectronics, sensing, and photonics.

Nanoelectronics is changing the way the world communicates, and is transforming our daily lives. Continuing Moore’s law and miniaturization of low-power semiconductor chips with ever-increasing functionality have been relentlessly driving R&D of new devices, materials, and process capabilities to meet performance, power, and cost requirements. This book covers up-to-date advances in research and industry practices in nanometrology, critical for continuing technology scaling and product innovation. It holistically approaches the subject matter and addresses emerging and important topics in semiconductor R&D and manufacturing. It is a complete guide for metrology and diagnostic techniques essential for process technology, electronics packaging, and product development and debugging—a unique approach compared to other books. The authors are from academia, government labs, and industry and have vast experience and expertise in the topics presented. The book is intended for all those involved in IC manufacturing and nanoelectronics and for those studying nanoelectronics process and assembly technologies or working in device testing, characterization, and diagnostic techniques.

In the past decade, driven by the demand for materials with high performance for next-generation semiconductor devices (e.g., for quantum computing), the exploration of III-V semiconductor materials and the design of improved devices based on these materials has extended to the nanometer scale, with several highlights in the studies of quantum wells, quantum dots, and nanowires (NW) in recent years. On the path of seeking smaller scale devices, the lateral scale is usually limited by the spatial resolution of the lithographic processes. Now, the challenge lies in the combination of semiconductor nanoscale structure with the desired electronic properties. Scaling down material synthesis to crystalline structures of only few atoms in size and precisely positioned in device configuration has not been realized so far. Moreover, the compatibility for large-scale industrial device processing is also challenging. In this dissertation, I present the surface characterization and studies of the modification of nanostructures on III-V semiconductor surfaces, with the techniques of low temperature scanning tunneling microscopy/spectroscopy (LT-STM/S) and X-ray photoelectron spectroscopy (XPS). Two main topics are Bi incorporation in GaAs (and InAs) surfaces and self-driven formation of nanostructures with atomic-scale precision. Different zinc blende and wurtzite crystal planes have been investigated, including the {11-20}- type facet which for GaAs and InAs uniquely exists on the side walls of NWs and nanoplatelets. The utilization of the tailored facets of NWs as templates for Bi-induced nanostructure formation has been explored as well. Bi-introduced low-dimensional nanostructures and exotic electronic states in III-V semiconductor systems have been investigated. The covalent bonds of Bi atoms in the self-formed Bi nanostructures on III-V substrates can vary depending on the substrate template and preparation condition, such as the Ga-Bi bonds in the 1D chain and 2D island nanostructures on Wz{11-20}-type facets on GaAs NWs. The possibility of tuning the self-formed III-V:Bi nanostructures in a more controllable way has been explored in this thesis. A significant high coverage of Bi on III-V semiconductor surface has been achieved. The observed variable bandgap and Bi-induced surface states are promising for applications in surface bandgap engineering and quantum technology components.

As we delve more deeply into the physics and chemistry of functional materials and processes, we are inexorably driven to the nanoscale. And nowhere is the development of instrumentation and associated techniques more important to scientific progress than in the area of nanoscience. The dramatic expansion of efforts to peer into nanoscale materials and processes has made it critical to capture and summarize the cutting-edge instrumentation and techniques that have become indispensable for scientific investigation in this arena. This Handbook is a key resource developed for scientists, engineers and advanced graduate students in which eminent scientists present the forefront of instrumentation and techniques for the study of structural, optical and electronic properties of semiconductor nanostructures.

Nanotechnology is a vital new area of research and development addressing the control, modification and fabrication of materials, structures and devices with nanometre precision and the synthesis of such structures into systems of micro- and macroscopic dimensions. Future applications of nanoscale science and technology include motors smaller than the diameter of a human hair and single-celled organisms programmed to fabricate materials with nanometer precision. Miniaturisation has revolutionised the semiconductor industry by making possible inexpensive integrated electronic circuits comprised of devices and wires with sub-micrometer dimensions. These integrated circuits are now ubiquitous, controlling everything from cars to toasters. The next level of miniaturisation, beyond sub-micrometer dimensions into nanoscale dimensions (invisible to the unaided human eye) is a booming area of research and development. This is a very hot area of research with large amounts of venture capital and government funding being invested worldwide, as such Nanoscale Science and Technology has a broad appeal based upon an interdisciplinary approach, covering aspects of physics, chemistry, biology, materials science and electronic engineering. Kelsall et al present a coherent approach to nanoscale sciences, which will be invaluable to graduate level students and researchers and practising engineers and product designers.

The Finite Element Method (FEM) has become an indispensable technology for the modelling and simulation of engineering systems. Written for engineers and students alike, the aim of the book is to provide the necessary theories and techniques of the FEM for readers to be able to use a commercial FEM package to solve primarily linear problems in mechanical and civil engineering with the main focus on structural mechanics and heat transfer. Fundamental theories are introduced in a straightforward way, and state-of-the-art techniques for designing and analyzing engineering systems, including microstructural systems are explained in detail. Case studies are used to demonstrate these theories, methods, techniques and practical applications, and numerous diagrams and tables are used throughout. The case studies and examples use the commercial software package ABAQUS, but the techniques explained are equally applicable for readers using other applications including NASTRAN, ANSYS, MARC, etc. A practical and accessible guide to this complex, yet important subject Covers modeling techniques that predict how components will operate and tolerate loads, stresses and strains in reality

Third volume of a 40volume series on nanoscience and nanotechnology, edited by the renowned scientist Challa S.S.R. Kumar. This handbook gives a comprehensive overview about Transmission electron microscopy characterization of nanomaterials. Modern applications and state-of-the-art techniques are covered and make this volume an essential reading for research scientists in academia and industry.