This report covers the sixth quarter, Phase II of a program on ion implanted planar GaAs integrated circuit technology. The bulk of the work on this program is carried out at the Rockwell International Electronics Research Center (ERC). Significant assistance is provided by three subcontractors; Crystal Specialties Inc. in crystal growth, California Institute of Technology in ion implantation and related materials technologies, and Cornell University in device modeling. With MSI circuit complexity well demonstrated, the circuit developement work in this quarter was focused on the testing of MSI/LSI circuits (250-500 gates), and on the design of an LSI circuit (1000 gates). The preliminary data from the MSI/LSI circuits (from mask set AR4) are promising. Although the 5X5 but parallel multiplier (260 gates) did not operate completely and did not function at its predicted speed, the test data indicate that it can meet the design expectations when a mask error (a missing connection on 16 gates) is corrected. The 2 X 32 stage shift register (550 gates) has functioned up to 33 stages involving approximately 300 gates. Further testing is scheduled. An 8 X 8 bit parallel multiplier (1008 gates) has been designed, layed out, and the mask set containing this circuit is being fabricated. Keywords: Semi insulating, Ion implantation, Integrated circuits, High speed logic, Gallium arsenides.
This report covers the third quarter, Phase II of a program on ion implanted planar GaAs integrated circuit technology. The overall objective of this program is the development of a manufacturable process for high-speed low-power GaAs logic circuits. The goal for Phase I was to establish the technology, and demonstrate its viability by fabricating circuits reaching MSI complexity. The goal for Phase II is to achieve the capability of fabricating GaAs ICs of LSI complexity. The program involves the Rockwell International Electronics Research Center and three subcontractors: Cal Tech, Cornell University and Crystal Specialties, Inc. The most important aspects of the work carried out in this quarter were the gaining of further insight into the causes for conversion of unqualified GaAs substrates, the fabrication of wafers with mask set AR3, and the preparation for evaluating the 3 x 3 parallel multiplier, a new circuit on AR3. This circuit will provide vital information for the design of the more complex circuits, on mask set AR4.
This report covers the fourth quarter of a program on LSI/VLSI ion implanted planar GaAs integrated circuit processing. The goal of this program is to realize the full potential of GaAs digital integrated circuits employing depletion mode MESFETs by developing the necessary processing methods and material capabilities to extend device complexity to VLSI. In the fourth quarter fabrication of the first wafers with mask set AR6, the last mask set to be employed with one inch wafers, was completed. Work on circuit reliability has continued, while process steps that may be limiting circuit yield are being investigated.
The unique properties of GaAs make it possible to construct integrated circuit devices that are impossible in Si. The Air Force Avionics Laboratory/AADR has been developing this technology for a number of years. The difficulty of introducing dopants by diffusion has lead ion implantation to play an increasing role in the fabrication process. The present production technique for high performance devices is to fabricate large quantities and select those few that meet the desired specifications. Having a nondestructive technique that can be used to characterize the implantation process during fabrication of the device so as to reject faulty device structures can save valuable time as well as money. Depth-resolved cathodoluminescence is a process that can be used for this purpose. This research develops and verifies a model of cathodoluminescence in ion implanted GaAs. This model can now be used as a tool for further study of ion implanted GaAs. This is the first step in developing cathodoluminescence as a tool for deducing the shape of the ion implanted depth profile in semiconductor materials. (Author).
Ion implantation is one of the key processing steps in silicon integrated circuit technology. Some integrated circuits require up to 17 implantation steps and circuits are seldom processed with less than 10 implantation steps. Controlled doping at controlled depths is an essential feature of implantation. Ion beam processing can also be used to improve corrosion resistance, to harden surfaces, to reduce wear and, in general, to improve materials properties. This book presents the physics and materials science of ion implantation and ion beam modification of materials. It covers ion-solid interactions used to predict ion ranges, ion straggling and lattice disorder. Also treated are shallow-junction formation and slicing silicon with hydrogen ion beams. Topics important for materials modification, such as ion-beam mixing, stresses, and sputtering, are also described.
VLSI Electronics Microstructure Science, Volume 11: GaAs Microelectronics presents the important aspects of GaAs (Gallium Arsenide) IC technology development ranging from materials preparation and IC fabrication to wafer evaluation and chip packaging. The volume is comprised of eleven chapters. Chapter 1 traces the historical development of GaAs technology for high-speed and high-frequency applications. This chapter summarizes the important properties of GaAs that serve to make this material and its related compounds technologically important. Chapter 2 covers GaAs substrate growth, ion implantation and annealing, and materials characterization, technologies that are essential for IC development. Chapters 3-6 describe the various IC technologies that are currently under development. These include microwave and digital MESFET ICs, the most mature technologies, and bipolar and field-effect heterostructure transistor ICs. The high-speed capability of GaAs ICs introduces new problems, on-wafer testing and packaging. These topics are discussed in Chapters 7 and 8. Applications for GaAs ICs are covered in Chapters 9 and 10. The first of these chapters is concerned with high speed computer applications; the second addresses military applications. The book concludes with a chapter on radiation effects in GaAs ICs. Scientists, engineers, researchers, device designers, and systems architects will find the book useful.
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.
