Integration of Ferroelectric HfO2 onto a III-V Nanowire Platform

The discovery of ferroelectricity in CMOS-compatible oxides, such as doped hafnium oxide, has opened new possibilities for electronics by reviving the use of ferroelectric implementations on modern technology platforms. This thesis presents the ground-up integration of ferroelectric HfO2 on a thermally sensitive III-V nanowire platform leading to the successful implementation of ferroelectric transistors (FeFETs), tunnel junctions (FTJs), and varactors for mm-wave applications. As ferroelectric HfO2 on III-V semiconductors is a nascent technology, a special emphasis is put on the fundamental integration issues and the various engineering challenges facing the technology.The fabrication of metal-oxide-semiconductor (MOS) capacitors is treated as well as the measurement methods developed to investigate the interfacial quality to the narrow bandgap III-V materials using both electrical and operando synchrotron light source techniques. After optimizing both the films and the top electrode, the gate stack is integrated onto vertical InAs nanowires on Si in order to successfully implement FeFETs. Their performance and reliability can be explained from the deeper physical understanding obtained from the capacitor structures.By introducing an InAs/(In)GaAsSb/GaSb heterostructure in the nanowire, a ferroelectric tunnel field effect transistor (ferro-TFET) is fabricated. Based on the ultra-short effective channel created by the band-to-band tunneling process, the localized potential variations induced by single ultra-scaled ferroelectric domains and individual defects are sensed and investigated. By intentionally introducing a gate-source overlap in the ferro-TFET, a non-volatile reconfigurable single-transistor solution for modulating an input signal with diverse modes including signal transmission, phase shift, frequency doubling, and mixing is implemented.Finally, by fabricating scaled ferroelectric MOS capacitors in the front-end with a dedicated and adopted RF and mm-wave backend-of-line (BEOL) implementation, the ferroelectric behavior is captured at RF and mm-wave frequencies

Broadband Permittivity Characterization of Tunable Dielectric Thin Films for Millimeter-wave Devices

The use of millimeter-wave carrier frequencies has the potential to revolutionize wireless telecommunications by providing a massive increase in available bandwidth. However, millimeter-wave communications are hindered by poor atmospheric and building penetration, and require complicated RF front-end architectures. Tunable dielectric thin films offer a fast, compact, and cost-effective way to overcome many of the challenges facing the use of millimeter-wave spectrum. Few materials have been characterized in the millimeter-wave regime where measurements become increasingly challenging as test signal wavelengths approach the physical size of devices. The few tunable dielectric materials that have been studied at these frequencies suffered from high dielectric loss or other limitations. In this dissertation, we address both the measurement and materials challenges that have limited the commercial implementation of tunable millimeter-wave devices. In this work, we describe our implementation of a unified on-wafer approach to measure the relative permittivity of thin films and substrates across a continuous frequency band from 100 Hz to 110 GHz. We achieve this ultra-wide bandwidth by combining electrical measurements of on-wafer planar capacitors and transmission lines, and use finite-element simulations to connect our electrical measurements to material properties. Motivated by the need for better tunable dielectrics, we also developed a high throughput technique to accelerate the discovery of tunable dielectric thin films. We discuss this technique, which is inspired by the principles of combinatorial materials science and the “Materials Genome Initiative”. Our technique enables the characterization of many unique material compositions using a single 10 mm composition-spread thin film chip. In addition to speeding up the synthesis, fabrication, and measurement steps, the single-sample nature of this approach provides extreme consistency in the processing variables that impact dielectric properties. Finally, we present another approach to tunable dielectric materials discovery with our development of (SrTiO3)n−1(BaTiO3)1SrO thin films incorporating “targeted chemical pressure”. These atomically-precise, strain-engineered superlattices achieve unparalleled performance, with measured relative tunability of almost 50 % and low dielectric loss even beyond 100 GHz. We discuss our use of the materials-by-design approach, which incorporates collaboration between theory, synthesis, and characterization, to overcome barriers to commercial integration without sacrificing advantageous material properties

Microscopy Conference 2017 (MC 2017) - Proceedings

Das Dokument enthält die Kurzfassungen der Beiträge aller Teilnehmer an der Mikroskopiekonferenz "MC 2017", die vom 21. bis 25.08.2017, in Lausanne stattfand

Microscopy Conference 2017 (MC 2017) - Proceedings

Das Dokument enthält die Kurzfassungen der Beiträge aller Teilnehmer an der Mikroskopiekonferenz "MC 2017", die vom 21. bis 25.08.2017, in Lausanne stattfand

Selected problems of materials science. Vol. 2. Nano-dielectrics metals in electronics. Mеtamaterials. Multiferroics. Nano-magnetics

The textbook examines physical foundations and practical application of current electronics materials. Modern theories are presented, more important experimental data and specifications of basic materials necessary for practical application are given. Contemporary research in the field of microelectronics and nanophysics is taken into account, while special attention is paid to the influence of the internal structure on the physical properties of materials and the prospects for their use. English-language lectures and other classes on the subject of the book are held at Igor Sikorsky Kyiv Polytechnic Institute at the departments of “Applied Physics” and “Microelectronics” on the subject of materials science, which is necessary for students of higher educational institutions when performing scientific works. For master’s degree applicants in specialty 105 “Applied physics and nanomaterials”.Розглянуто фізичні основи та практичне застосування актуальних матеріалів електроніки. Подано сучасні теорії, наведено найважливіші експериментальні дані та специфікації основних матеріалів, які потрібні для практичного застосування. Враховано сучасні дослідження у галузі мікроелектроніки та нанофізики, при цьому особливу увагу приділено впливу внутрішньої структури на фізичні властивості матеріалів і на перспективи їх використання. Англомовні лекції та інші види занять за тематикою книги проводяться в КПІ ім. Ігоря Сікорського на кафедрах «Прикладна фізика» та «Мікро-електроніка» за напрямом матеріалознавство, що необхідно студентам вищих навчальних закладів при виконанні наукових робіт. Для здобувачів магістратури за спеціальністю 105 «Прикладна фізика та наноматеріали»