Ohmic Contacts for Gallium Arsenide Devices


Book Description

A study was made of various metals and metal alloys (Ag, Ni, In, and Au-Zn) which would make ohmic contacts to p- or n-type GaAs to determine the value of contact resistivity as a function of substrate impurity concentration. Contact resistivity values for p-type material varied from 1.2 x 10 to the -4th power ohm-cm sq for 2.8 x 10 to the 17th power/cc to 7.3 x 10 to the -7th ohm-cm sq for 9 x 10 to the 19th power/cc, and for n-type material from 2.5 x 10 to the -4th power ohm-cm sq for 1 x 10 to the 17th power/cc to 1.5 x 10 to the -5th power ohm-cm sq for 3 x 10 to the 18th power/cc. The metals were applied by evaporation or plating and followed by microalloying. The improvement in contact resistivity, as substrate impurity concentration increases, indicates the desirability of incorporating a thin, heavily doped region at the surface of a device by means of diffusion or epitaxy. The improvement in power output for a typical laser diode and its modified versions resulting from the reduction in R sub s is compared. (Author).




Fabrication of GaAs Devices


Book Description

This book provides fundamental and practical information on all aspects of GaAs processing and gives pragmatic advice on cleaning and passivation, wet and dry etching and photolithography. Other topics covered include device performance for HBTs (Heterojunction Bipolar Transistors) and FETs (Field Effect Transistors), how these relate to processing choices, and special processing issues such as wet oxidation, which are especially important in optoelectronic devices. This book is suitable for both new and practising engineers.










GaAs Devices and Circuits


Book Description

GaAs devices and integrated circuits have emerged as leading contenders for ultra-high-speed applications. This book is intended to be a reference for a rapidly growing GaAs community of researchers and graduate students. It was written over several years and parts of it were used for courses on GaAs devices and integrated circuits and on heterojunction GaAs devices developed and taught at the University of Minnesota. Many people helped me in writing this book. I would like to express my deep gratitude to Professor Lester Eastman of Cornell University, whose ideas and thoughts inspired me and helped to determine the direction of my research work for many years. I also benefited from numerous discussions with his students and associates and from the very atmosphere of the pursuit of excellence which exists in his group. I would like to thank my former and present co-workers and colleagues-Drs. Levinstein and Gelmont of the A. F. Ioffe Institute of Physics and Technology, Professor Melvin Shaw of Wayne State University, Dr. Kastalsky of Bell Communi cations, Professor Gary Robinson of Colorado State University, Professor Tony Valois, and Dr. Tim Drummond of Sandia Labs-for their contributions to our joint research and for valuable discussions. My special thanks to Professor Morko.;, for his help, his ideas, and the example set by his pioneering work. Since 1978 I have been working with engineers from Honeywell, Inc.-Drs.







GaAs High-Speed Devices


Book Description

The performance of high-speed semiconductor devices—the genius driving digital computers, advanced electronic systems for digital signal processing, telecommunication systems, and optoelectronics—is inextricably linked to the unique physical and electrical properties of gallium arsenide. Once viewed as a novel alternative to silicon, gallium arsenide has swiftly moved into the forefront of the leading high-tech industries as an irreplaceable material in component fabrication. GaAs High-Speed Devices provides a comprehensive, state-of-the-science look at the phenomenally expansive range of engineering devices gallium arsenide has made possible—as well as the fabrication methods, operating principles, device models, novel device designs, and the material properties and physics of GaAs that are so keenly integral to their success. In a clear five-part format, the book systematically examines each of these aspects of GaAs device technology, forming the first authoritative study to consider so many important aspects at once and in such detail. Beginning with chapter 2 of part one, the book discusses such basic subjects as gallium arsenide materials and crystal properties, electron energy band structures, hole and electron transport, crystal growth of GaAs from the melt and defect density analysis. Part two describes the fabrication process of gallium arsenide devices and integrated circuits, shedding light, in chapter 3, on epitaxial growth processes, molecular beam epitaxy, and metal organic chemical vapor deposition techniques. Chapter 4 provides an introduction to wafer cleaning techniques and environment control, wet etching methods and chemicals, and dry etching systems, including reactive ion etching, focused ion beam, and laser assisted methods. Chapter 5 provides a clear overview of photolithography and nonoptical lithography techniques that include electron beam, x-ray, and ion beam lithography systems. The advances in fabrication techniques described in previous chapters necessitate an examination of low-dimension device physics, which is carried on in detail in chapter 6 of part three. Part four includes a discussion of innovative device design and operating principles which deepens and elaborates the ideas introduced in chapter 1. Key areas such as metal-semiconductor contact systems, Schottky Barrier and ohmic contact formation and reliability studies are examined in chapter 7. A detailed discussion of metal semiconductor field-effect transistors, the fabrication technology, and models and parameter extraction for device analyses occurs in chapter 8. The fifth part of the book progresses to an up-to-date discussion of heterostructure field-effect (HEMT in chapter 9), potential-effect (HBT in chapter 10), and quantum-effect devices (chapters 11 and 12), all of which are certain to have a major impact on high-speed integrated circuits and optoelectronic integrated circuit (OEIC) applications. Every facet of GaAs device technology is placed firmly in a historical context, allowing readers to see instantly the significant developmental changes that have shaped it. Featuring a look at devices still under development and device structures not yet found in the literature, GaAs High-Speed Devices also provides a valuable glimpse into the newest innovations at the center of the latest GaAs technology. An essential text for electrical engineers, materials scientists, physicists, and students, GaAs High-Speed Devices offers the first comprehensive and up-to-date look at these formidable 21st century tools. The unique physical and electrical properties of gallium arsenide has revolutionized the hardware essential to digital computers, advanced electronic systems for digital signal processing, telecommunication systems, and optoelectronics. GaAs High-Speed Devices provides the first fully comprehensive look at the enormous range of engineering devices gallium arsenide has made possible as well as the backbone of the technology—ication methods, operating principles, and the materials properties and physics of GaAs—device models and novel device designs. Featuring a clear, six-part format, the book covers: GaAs materials and crystal properties Fabrication processes of GaAs devices and integrated circuits Electron beam, x-ray, and ion beam lithography systems Metal-semiconductor contact systems Heterostructure field-effect, potential-effect, and quantum-effect devices GaAs Microwave Monolithic Integrated Circuits and Digital Integrated Circuits In addition, this comprehensive volume places every facet of the technology in an historical context and gives readers an unusual glimpse at devices still under development and device structures not yet found in the literature.




Gallium Arsenide


Book Description

This is the seventh volume in the Wiley Series in Solid State Devices and Circuits, and deals comprehensively with the use of gallium arsenide for high frequency and high speed circuits.







Metal – Semiconductor Contacts and Devices


Book Description

VLSI Electronics Microstructure Science, Volume 13: Metal-Semiconductor Contacts and Devices presents the physics, technology, and applications of metal-semiconductor barriers in digital integrated circuits. The emphasis is placed on the interplay among the theory, processing, and characterization techniques in the development of practical metal-semiconductor contacts and devices. This volume contains chapters that are devoted to the discussion of the physics of metal-semiconductor interfaces and its basic phenomena; fabrication procedures; and interface characterization techniques, particularly, ohmic contacts. Contacts that involve polycrystalline silicon; applications of the metal-semiconductor barriers in MOS, bipolar, and MESFET digital integrated circuits; and methods for measuring the barrier height are covered as well. Process engineers, device physicists, circuit designers, and students of this discipline will find the book very useful.