Development Of Silicon Germanium Based Quantum Dots For Nanoelectronic Device Applications

Abstract: As CMOS dimensions decrease each year, the International Technology Roadmap for Semiconductors (ITRS) encourages development of "emerging research devices" to eventually replace CMOS. SiGe-based quantum dots, the focus of this study, are attractive because they can be integrated with existing Si -based devices and fabricated using existing processes. This process exploits self-limiting effects in Si nanopillar oxidation and Ge segregation during SiGe oxidation to fabricate uniformly sized Ge quantum dots suitable for room temperature operation. In this study, four fabrication processes were investigated: electron-beam lithography (EBL), inductively-coupled plasma (ICP) etching, thermal oxidation, and transmission electron microscopy (TEM). The samples consisted of rows of closely spaced Si nanopillars, with diameters of 25-100 nm and heights of 80-600 nm.

Nanostructured silicon-germanium (SiGe) opens up the prospects of novel and enhanced electronic device performance, especially for semiconductor devices. Silicon-germanium (SiGe) nanostructures reviews the materials science of nanostructures and their properties and applications in different electronic devices. The introductory part one covers the structural properties of SiGe nanostructures, with a further chapter discussing electronic band structures of SiGe alloys. Part two concentrates on the formation of SiGe nanostructures, with chapters on different methods of crystal growth such as molecular beam epitaxy and chemical vapour deposition. This part also includes chapters covering strain engineering and modelling. Part three covers the material properties of SiGe nanostructures, including chapters on such topics as strain-induced defects, transport properties and microcavities and quantum cascade laser structures. In Part four, devices utilising SiGe alloys are discussed. Chapters cover ultra large scale integrated applications, MOSFETs and the use of SiGe in different types of transistors and optical devices. With its distinguished editors and team of international contributors, Silicon-germanium (SiGe) nanostructures is a standard reference for researchers focusing on semiconductor devices and materials in industry and academia, particularly those interested in nanostructures. Reviews the materials science of nanostructures and their properties and applications in different electronic devices Assesses the structural properties of SiGe nanostructures, discussing electronic band structures of SiGe alloys Explores the formation of SiGe nanostructuresfeaturing different methods of crystal growth such as molecular beam epitaxy and chemical vapour deposition

The discovery of quantum dots has contributed in creating the entire new field of nanotechnology. Semiconductor quantum dots in particular have promised a new leap for semiconductor devices, decreasing devices sizes from m and mm scales to nanoscales. Applications for such devices range from high-density data storage to nanoscale lasers integrated directly into computer chips and other integrated circuits, providing optical data transmission far superior to present day "Copper technology", directly between electronic components. The problem has been to create these quantum dots and the thesis project behind this book addresses this problem for group-IV semiconductors which are the most widely used material in present-day semiconductor technology. The thesis delivers a review of previous results in this field and investigate the possibility of (and attempt) growing Germanium quantum dots in Silicon. As it turns out - not to anticipate the conclusion - this does not seem to be possible with pure grown Germanium dots in Silicon, but other paths might be possible. The book aims for academics, professionals and others with interest in nanoscale electronics.

Quantum dots as nanomaterials have been extensively investigated in the past several decades from growth to characterization to applications. As the basis of future developments in the field, this book collects a series of state-of-the-art chapters on the current status of quantum dot devices and how these devices take advantage of quantum features. Written by 56 leading experts from 14 countries, the chapters cover numerous quantum dot applications, including lasers, LEDs, detectors, amplifiers, switches, transistors, and solar cells. Quantum Dot Devices is appropriate for researchers of all levels of experience with an interest in epitaxial and/or colloidal quantum dots. It provides the beginner with the necessary overview of this exciting field and those more experienced with a comprehensive reference source.

Since first developed in the early sixties, silicon chip technology has made vast leaps forward. From a rudimentary circuit with a mere handful of transistors, the chip has evolved into a technological wonder, packing millions of bits of information on a surface no larger that a human thumbnail. And most experts predict that in the near future, we will see chips with over a billion bits. Quantum dots are small devices that contain a tiny droplet of free electrons. They are fabricated in semiconductor materials and have typical dimensions ranging from nanometres to a few microns. The size and shape of these structures and therefore the number of electrons they contain can be precisely controlled; a quantum dot can have anything from a single electron to a collection of several thousands. The physics of quantum dots shows many parallels with the behaviour of naturally occurring quantum systems in atomic and nuclear physics. As in an atom, the energy levels in a quantum dot become quantised due to the confinement of electrons. Unlike atoms however, quantum dots can be easily connected to electrodes and are therefore excellent tools for studying atomic-like properties. This new book presents the latest research developments in the world.

Brings novel insights to a vibrant research area with high application potential?covering materials, physics, architecture, and integration aspects of future generation CMOS electronics technology Over the last four decades we have seen tremendous growth in semiconductor electronics. This growth has been fueled by the matured complementary metal oxide semiconductor (CMOS) technology. This comprehensive book captures the novel device options in CMOS technology that can be realized using non-silicon semiconductors. It discusses germanium, III-V materials, carbon nanotubes and graphene as semiconducting materials for three-dimensional field-effect transistors. It also covers non-conventional materials such as nanowires and nanotubes. Additionally, nanoelectromechanical switches-based mechanical relays and wide bandgap semiconductor-based terahertz electronics are reviewed as essential add-on electronics for enhanced communication and computational capabilities. Advanced Nanoelectronics: Post-Silicon Materials and Devices begins with a discussion of the future of CMOS. It continues with comprehensive chapter coverage of: nanowire field effect transistors; two-dimensional materials for electronic applications; the challenges and breakthroughs of the integration of germanium into modern CMOS; carbon nanotube logic technology; tunnel field effect transistors; energy efficient computing with negative capacitance; spin-based devices for logic, memory and non-Boolean architectures; and terahertz properties and applications of GaN. -Puts forward novel approaches for future, state-of-the-art, nanoelectronic devices -Discusses emerging materials and architectures such as alternate channel material like germanium, gallium nitride, 1D nanowires/tubes, 2D graphene, and other dichalcogenide materials and ferroelectrics -Examines new physics such as spintronics, negative capacitance, quantum computing, and 3D-IC technology -Brings together the latest developments in the field for easy reference -Enables academic and R&D researchers in semiconductors to "think outside the box" and explore beyond silica An important resource for future generation CMOS electronics technology, Advanced Nanoelectronics: Post-Silicon Materials and Devices will appeal to materials scientists, semiconductor physicists, semiconductor industry, and electrical engineers.

Si/SiGe quantum dots (QDs) are promising candidates for spin-based quantum bits (qubits) as a result of the reduced spin-orbit coupling as well as the Si isotopes with zero nuclear spin. Meanwhile qubit readout is a challenge related to semiconductor-based quantum computation. A superconducting single-electron transistor (SET), when operating in the radio-frequency (rf) regime, has a combination of high charge sensitivity and low back-action and can potentially become an ideal charge sensor for the QDs. This thesis describes the development of superconducting SET charge sensors for Si/SiGe QDs. Using rf-SETs we have detected real-time electron tunneling events on the order of 10 microseconds in a single QD and mapped out the stability diagram of a double QD, showing spin blockade and bias triangles due to excited-state transitions. In addition Kondo effects that are significantly different from the standard spin 1/2 model have been observed and investigated in both perpendicular and in-plane magnetic fields, indicating the interplay between the spin and valley degrees of freedom in Si.

The series Topics in Current Chemistry Collections presents critical reviews from the journal Topics in Current Chemistry organized in topical volumes. The scope of coverage is all areas of chemical science including the interfaces with related disciplines such as biology, medicine and materials science. The goal of each thematic volume is to give the non-specialist reader, whether in academia or industry, a comprehensive insight into an area where new research is emerging which is of interest to a larger scientific audience. Each review within the volume critically surveys one aspect of that topic and places it within the context of the volume as a whole. The most significant developments of the last 5 to 10 years are presented using selected examples to illustrate the principles discussed. The coverage is not intended to be an exhaustive summary of the field or include large quantities of data, but should rather be conceptual, concentrating on the methodological thinking that will allow the non-specialist reader to understand the information presented. Contributions also offer an outlook on potential future developments in the field.

This multidisciplinary book provides up-to-date coverage of carrier and spin dynamics and energy transfer and structural interaction among nanostructures. Coverage also includes current device applications such as quantum dot lasers and detectors, as well as future applications to quantum information processing. The book will serve as a reference for anyone working with or planning to work with quantum dots.