Download or read book Microstructural Buffer Effects in AlGaN GaN High Electron Mobility Transistors written by Markus Wohlfahrt and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Study of the Effects of GaN Buffer Layer Quality on the Dc Characteristics of AlGaN GaN High Electron Mobility Transistors written by and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Here we studied the effect of buffer layer quality on dc characteristics of AlGaN/GaN high electron mobility (HEMTs). AlGaN/GaN HEMT structures with 2 and 5 [mu]m GaN buffer layers on sapphire substrates from two different vendors with the same Al concentration of AlGaN were used. The defect densities of HEMT structures with 2 and 5 [mu]m GaN buffer layer were 7 × 109 and 5 × 108 cm2, respectively, as measured by transmission electron microscopy. There was little difference in drain saturation current or in transfer characteristics in HEMTs on these two types of buffer. However, there was no dispersion observed on the nonpassivated HEMTs with 5 [mu]m GaN buffer layer for gate-lag pulsed measurement at 100 kHz, which was in sharp contrast to the 71% drain current reduction for the HEMT with 2 [mu]m GaN buffer layer.

Download or read book Analysis and Optimization of AlGaN GaN High Electron Mobility Transistors for Microwave Applications written by Michael Hosch and published by Cuvillier Verlag. This book was released on 2011-08-08 with total page 129 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis deals with the analysis and optimization of some of the most prominent non-ideal effects in AlGaN/GaN high electron mobility transistors used in microwave applications as well as the optimization of the RF gain. The effect of current collapse, the root cause of leakage currents as well as field-dependent self-heating effects have been investigated by eletrical characterization using well established techniques and have been analyzed using 2-dimensional physical device simulations. It will be shown that the origin of all effects is strongly related to the device surface and some are even competing effects making device optimization a challenge. However, a detailed localization of the regions affecting device performance will be given leading to a better understanding for fabrication process optimization. Finally, I simulation study is conducted giving suggestions for RF gain improvement based on very simple device layout variations.

Download or read book Power GaN Devices written by Matteo Meneghini and published by Springer. This book was released on 2016-09-08 with total page 383 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents the first comprehensive overview of the properties and fabrication methods of GaN-based power transistors, with contributions from the most active research groups in the field. It describes how gallium nitride has emerged as an excellent material for the fabrication of power transistors; thanks to the high energy gap, high breakdown field, and saturation velocity of GaN, these devices can reach breakdown voltages beyond the kV range, and very high switching frequencies, thus being suitable for application in power conversion systems. Based on GaN, switching-mode power converters with efficiency in excess of 99 % have been already demonstrated, thus clearing the way for massive adoption of GaN transistors in the power conversion market. This is expected to have important advantages at both the environmental and economic level, since power conversion losses account for 10 % of global electricity consumption. The first part of the book describes the properties and advantages of gallium nitride compared to conventional semiconductor materials. The second part of the book describes the techniques used for device fabrication, and the methods for GaN-on-Silicon mass production. Specific attention is paid to the three most advanced device structures: lateral transistors, vertical power devices, and nanowire-based HEMTs. Other relevant topics covered by the book are the strategies for normally-off operation, and the problems related to device reliability. The last chapter reviews the switching characteristics of GaN HEMTs based on a systems level approach. This book is a unique reference for people working in the materials, device and power electronics fields; it provides interdisciplinary information on material growth, device fabrication, reliability issues and circuit-level switching investigation.

Download or read book Design Growth and Characterization of AlGaN GaN High Electron Mobility Transistors written by Michael James Murphy and published by . This book was released on 2000 with total page 226 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Polarization Effects in Semiconductors written by Debdeep Jena and published by Springer Science & Business Media. This book was released on 2008 with total page 523 pages. Available in PDF, EPUB and Kindle. Book excerpt: Polarization Effects in Semiconductors: From Ab Initio Theory to Device Applications presents the latest understanding of the solid state physics, electronic implications and practical applications of the unique spontaneous or pyro-electric polarization charge of wurtzite compound semiconductors, and associated piezo-electric effects in strained thin film heterostructures. These heterostructures are used in wide band gap semiconductor based sensors, in addition to various electronic and opto-electronic semiconductor devices. The book covers the ab initio theory of polarization in cubic and hexagonal semiconductors, growth of thin film GaN, GaN/AlGaN GaAlN/ AlGaInN, and other nitrides, and SiC heterostructures. It discusses the effects of spontaneous and piezoelectric polarization on band diagrams and electronic properties of abrupt and compositionally graded heterostructures, electronic characterization of polarization-induced charge distributions by scanning-probe spectroscopies, and gauge factors and strain effects. In addition, polarization in extended defects, piezo-electric strain/charge engineering, and application to device design and processing are covered. The effects of polarization on the fundamental electron transport properties, and on the basic optical transitions are described. The crucial role of polarization in devices such as high electron mobility transistors (HEMTs) and light-emitting diodes (LEDs) is covered. The chapters are authored by professors and researchers in the fields of physics, applied physics and electrical engineering, who worked for 5 years under the "Polarization Effects in Semiconductors" DOD funded Multi Disciplinary University Research Initiative. This book will be of interest to graduate students and researchers working in the field of wide-bandgap semiconductor physics and their device applications. It will also be useful for practicing engineers in the field of wide-bandgap semiconductor device research and development.

Download or read book Surface and Mechanical Stress Effects in AlGaN GaN High Electron Mobility Transistors written by Sameer Jayanta Joglekar and published by . This book was released on 2017 with total page 161 pages. Available in PDF, EPUB and Kindle. Book excerpt: Gallium Nitride (GaN) belongs to a class of materials called wide band-gap semiconductors. In recent years, the versatile nature of this material has been exploited for a wide range of applications from solid state lighting to RF and microwave communication, as well as high power switching. The first part of this thesis discusses planar AlGaN/GaN transistors. GaN is a piezoelectric material, and changes in mechanical stress result in a change in the charge density which in turn affects the maximum current in AlGaN/GaN transistors. Finite element modelling techniques were applied to quantify the mechanical stress distribution in planar AlGaN/GaN RF transistors resulting from device fabrication, and operation in the on- and off-state. Thereafter, two important surface and interface effects were studied in this thesis. In the first one, the impact of surface cleanings, surface treatments and plasma-based dry etch conditions on two different types of ohmic contact technologies was investigated. Contact resistance measurements were correlated with surface characterization results. The second was that of interface positive charges at the Al2O3-GaN interface and the increase in electron density in the device resulting from them. In both these problems, a combination of device electrical measurements and material characterization techniques was used to establish direct correlations between device behavior and material properties. The second part of the thesis deals exclusively with nano-ribbon (NR) or fin-like AlGaN/GaN transistors. Fundamental transport properties of charge density and mobility in NR devices were studied in order to understand the difference in behavior of these devices from planar devices. The influence of passivation films on the charge density in these structures was investigated, using Al2O3 passivation as a specific example. Electron mobility degradation due to sidewall-scattering in NR devices was quantified using different mobility extraction methods based on device measurements. The thesis concludes with a potential application of NR AlGaN/GaN transistors for high linearity power amplification. A new kind of transistor with varying threshold voltages along the gate width is proposed to improve the DC and RF linearity of GaN-based devices.

Download or read book A Study of Effect of Stress on the AlGaN GaN High Electron Mobility Transistor written by 徐啓桓 and published by . This book was released on 2019 with total page 70 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Wide Bandgap Based Devices written by Farid Medjdoub and published by MDPI. This book was released on 2021-05-26 with total page 242 pages. Available in PDF, EPUB and Kindle. Book excerpt: Emerging wide bandgap (WBG) semiconductors hold the potential to advance the global industry in the same way that, more than 50 years ago, the invention of the silicon (Si) chip enabled the modern computer era. SiC- and GaN-based devices are starting to become more commercially available. Smaller, faster, and more efficient than their counterpart Si-based components, these WBG devices also offer greater expected reliability in tougher operating conditions. Furthermore, in this frame, a new class of microelectronic-grade semiconducting materials that have an even larger bandgap than the previously established wide bandgap semiconductors, such as GaN and SiC, have been created, and are thus referred to as “ultra-wide bandgap” materials. These materials, which include AlGaN, AlN, diamond, Ga2O3, and BN, offer theoretically superior properties, including a higher critical breakdown field, higher temperature operation, and potentially higher radiation tolerance. These attributes, in turn, make it possible to use revolutionary new devices for extreme environments, such as high-efficiency power transistors, because of the improved Baliga figure of merit, ultra-high voltage pulsed power switches, high-efficiency UV-LEDs, and electronics. This Special Issue aims to collect high quality research papers, short communications, and review articles that focus on wide bandgap device design, fabrication, and advanced characterization. The Special Issue will also publish selected papers from the 43rd Workshop on Compound Semiconductor Devices and Integrated Circuits, held in France (WOCSDICE 2019), which brings together scientists and engineers working in the area of III–V, and other compound semiconductor devices and integrated circuits. In particular, the following topics are addressed: – GaN- and SiC-based devices for power and optoelectronic applications – Ga2O3 substrate development, and Ga2O3 thin film growth, doping, and devices – AlN-based emerging material and devices – BN epitaxial growth, characterization, and devices

Download or read book Qualitative and Quantative Characterization of Trapping Effects in AlGaN GaN High Electron Mobility Transistors written by Hyeong Nam Kim and published by . This book was released on 2009 with total page 195 pages. Available in PDF, EPUB and Kindle. Book excerpt: Based on temperature-dependent drain current transients, it was demonstrated that PGA modifies trap activity in AlGaN/GaN HEMTs. The PGA process removes shallow traps with an activation energy of ~ 38 meV and tE of ~ 0.5 us at 295 K and induces deeper traps at least with an activation energy of ~ 0.31 eV and tE of ~ 21.6 us at 295 K. Shallow traps result in fast drain current transient and high reverse gate leakage current while deep traps lead to slow current recovery but a small leakage current.

Download or read book Current Collapse Induced in AlGaN GaN High Electron Mobility Transistors by Bias Stress written by and published by . This book was released on 2003 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt: Current collapse is observed to be induced in AlGaN/GaN high-electron-mobility transistors as a result of short-term bias stress. This effect was seen in devices grown by both metalorganic chemical vapor deposition (MOCVD) and molecular-beam epitaxy (MBE). The induced collapse appears to be permanent and can be reversed by SiN passivation. The traps responsible for the collapse have been studied by photoionization spectroscopy. For the MOCVD-grown devices, the same traps cause the collapse in both unstressed and stressed devices. These effects are thought to result from hot-carrier damage during stress.

Download or read book Piezotronics and Piezo Phototronics written by Zhong Lin Wang and published by Springer Science & Business Media. This book was released on 2013-01-11 with total page 254 pages. Available in PDF, EPUB and Kindle. Book excerpt: The fundamental principle of piezotronics and piezo-phototronics were introduced by Wang in 2007 and 2010, respectively. Due to the polarization of ions in a crystal that has non-central symmetry in materials, such as the wurtzite structured ZnO, GaN and InN, a piezoelectric potential (piezopotential) is created in the crystal by applying a stress. Owing to the simultaneous possession of piezoelectricity and semiconductor properties, the piezopotential created in the crystal has a strong effect on the carrier transport at the interface/junction. Piezotronics is for devices fabricated using the piezopotential as a “gate” voltage to control charge carrier transport at a contact or junction. The piezo-phototronic effect uses the piezopotential to control the carrier generation, transport, separation and/or recombination for improving the performance of optoelectronic devices, such as photon detector, solar cell and LED. The functionality offered by piezotroics and piezo-phototronics are complimentary to CMOS technology. There is an effective integration of piezotronic and piezo-phototronic devices with silicon based CMOS technology. Unique applications can be found in areas such as human-computer interfacing, sensing and actuating in nanorobotics, smart and personalized electronic signatures, smart MEMS/NEMS, nanorobotics and energy sciences. This book introduces the fundamentals of piezotronics and piezo-phototronics and advanced applications. It gives guidance to researchers, engineers and graduate students.

Download or read book Fabrication and Characterization of AlGaN GaN High Electron Mobility Transistors written by Peter Javorka and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Effects of Polycrystalline AlN Film on the Dynamic Performance of AlGaN GaN High Electron Mobility Transistors written by and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Effects of Post annealing on the Passivation Interface Characteristics of AlGaN GaN High Electron Mobility Transistors written by and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Modeling of AlGaN GaN High Electron Mobility Transistors written by D. Nirmal and published by Springer. This book was released on 2025-02-11 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume focuses on GaN HEMT, the most promising transistor technology for RF power applications such as 5G communications, space and defense. The contents include accurate small signal models required to predict the RF power performance of RF electronic circuits, large signal modeling of GaN HEMTs, accurate and compact physical models to assist the RF circuit designers to optimize GaN HEMT-based power amplifiers and integrated circuits, among others. The book also covers thermal resistance modeling of GaN HEMTs, charge-based compact models, and surface potential-based models to study the impact of gate leakage current on the RF power performance of GaN HEMTs. This book also deals with the analytical modeling of intrinsic charges and surface potential of GaN HEMTs, physical modeling of charge trapping, neural network-based GaN HEMT models, numerical-based GaN HEMT models, modeling of short channel effects in GaN HEMTs, modeling of parasitic capacitances and resistances, modelingof current collapse and kink effects in HGaN HEMTs, etc. This volume will be a useful to those in industry and academia.

Download or read book Fabrication and Characterisation of AlGaN GaN High Electron Mobility Transistors for Power Applications written by Juraj Bernát and published by . This book was released on 2005 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: