ULTRARAM™:Design, Modelling, Fabrication and Testing of Ultra-low-power III-V Memory Devices and Arrays

In this thesis, a novel memory based on III-V compound semiconductors is studied, both theoretically and experimentally, with the aim of developing a technology with superior performance capabilities to established and emerging rival memories. This technology is known as ULTRARAM™. The memory concept is based on quantum resonant tunnelling through InAs/AlSb heterostructures, which are engineered to only allow electron tunnelling at precise energy alignment(s) when a bias is applied. The memory device features a floating gate (FG) as the storage medium, where electrons that tunnel through the InAs/AlSb heterostructure are confined in the FG to define the memory logic (0 or 1). The large conduction band offset of the InAs/AlSb heterojunction (2.1 eV) keeps electrons in the FG indefinitely, constituting a non-volatile logic state. Electrons can be removed from the FG via a similar resonant tunnelling process by reversing the voltage polarity. This concept shares similarities with flash memory, however the resonant tunnelling mechanism provides ultra-low-power, low-voltage, high-endurance and high-speed switching capability. The quantum tunnelling junction is studied in detail using the non-equilibrium Green’s function (NEGF) method. Then, Poisson-Schrödinger simulations are used to design a high-contrast readout procedure for the memory using the unusual type-III band-offset of the InAs/GaSb heterojunction. With the theoretical groundwork for the technology laid out, the memory performance is modelled and a high-density ULTRARAM™ memory architecture is proposed for random-access memory applications. Later, NEGF calculations are used for a detailed study of the process tolerances in the tunnelling region required for ULTRARAM™ large-scale wafer manufacture. Using interfacial misfit array growth techniques, III-V layers (InAs, AlSb and GaSb) for ULTRARAM™ were successfully implemented on both GaAs and Si substrates. Single devices and 2×2 arrays were then fabricated using a top-down processing approach. The memories demonstrated outstanding memory performance on both substrate materials at 10, 20 and 50 µm gate lengths at room temperature. Non-volatile switching was obtained with ≤ 2.5 V pulses, corresponding to a switching energy per unit area that is lower than DRAM and flash by factors of 100 and 1000 respectively. Memory logic was retained for over 24 hours whilst undergoing over 10^6 readout operations. Analysis of the retention data suggests a storage time exceeding 1000 years. Devices showed promising durability results, enduring over 10^7 cycles without degradation, at least two orders of magnitude improvement over flash memory. Switching of the cell’s logic was possible at 500 µs pulse durations for a 20 µm gate length, suggesting a subns switching time if scaled to modern-day feature sizes. The proposed half-voltage architecture is shown to operate in principle, where the memory state is preserved during a disturbance test of > 10^5 half-cycles. With regard to the device physics, these findings point towards ULTRARAM™ as a universal memory candidate. The path towards future commercial viability relies on process development for aggressive device and array-size scaling and implementation on larger Si wafe

Topical Workshop on Electronics for Particle Physics

The purpose of the workshop was to present results and original concepts for electronics research and development relevant to particle physics experiments as well as accelerator and beam instrumentation at future facilities; to review the status of electronics for the LHC experiments; to identify and encourage common efforts for the development of electronics; and to promote information exchange and collaboration in the relevant engineering and physics communities

NASA Tech Briefs, April 1990

Topics: New Product Ideas; NASA TU Services; Electronic Components and Circuits; Electronic Systems; Physical Sciences; Materials; Computer Programs; Mechanics; Machinery; Fabrication Technology; Mathematics and Information Sciences

NASA Tech Briefs, July 1993

Topics include: Data Acquisition and Analysis: Electronic Components and Circuits; Electronic Systems; Physical Sciences; Materials; Computer Programs; Mechanics; Machinery; Fabrication Technology; Mathematics and Information Sciences; Life Sciences

NASA Tech Briefs, February 1994

Topics covered include: Test and Measurement; Electronic Components and Circuits; Electronic Systems; Physical Sciences; Materials; Computer Programs; Mechanics; Machinery; Fabrication Technology; Mathematics and Information Sciences; Life Sciences; Books and Report

Technology 2004, Vol. 2

Proceedings from symposia of the Technology 2004 Conference, November 8-10, 1994, Washington, DC. Volume 2 features papers on computers and software, virtual reality simulation, environmental technology, video and imaging, medical technology and life sciences, robotics and artificial intelligence, and electronics

NASA Tech Briefs, February 2002

Topics include:a technology focus on computers, electronic components and systems, software, materials, mechanics,physical sciences machinery, manufacturing/fabrication, mathematics, book and reports, motion control tech briefs and a special section on Photonics Tech Briefs

Technology 2001: The Second National Technology Transfer Conference and Exposition, volume 1

Papers from the technical sessions of the Technology 2001 Conference and Exposition are presented. The technical sessions featured discussions of advanced manufacturing, artificial intelligence, biotechnology, computer graphics and simulation, communications, data and information management, electronics, electro-optics, environmental technology, life sciences, materials science, medical advances, robotics, software engineering, and test and measurement

Muon (g-2) Technical Design Report

The Muon (g-2) Experiment, E989 at Fermilab, will measure the muon anomalous magnetic moment a factor-of-four more precisely than was done in E821 at the Brookhaven National Laboratory AGS. The E821 result appears to be greater than the Standard-Model prediction by more than three standard deviations. When combined with expected improvement in the Standard-Model hadronic contributions, E989 should be able to determine definitively whether or not the E821 result is evidence for physics beyond the Standard Model. After a review of the physics motivation and the basic technique, which will use the muon storage ring built at BNL and now relocated to Fermilab, the design of the new experiment is presented. This document was created in partial fulfillment of the requirements necessary to obtain DOE CD-2/3 approval

1995 BRAC Commission

Naval Research Lab: Special Facilities and Equipment Capability Data Call. Tabular data, memos, documents. Box 178, L-110