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Barnaby, Hugh

Publications and source records attributed to Barnaby, Hugh.

14 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

Investigating the Effects of Individual Neutron-Induced Defects in Bipolar Junction Transistors

Here, this study investigates neutron-induced displacement damage in Bipolar Junction Transistors (BJTs) using TCAD models informed by Deep-Level-Transient-Spectroscopy (DLTS) data. These models are calibrated and validated against experimental measurements performed at various neutron fluences. Both npn and pnp transistor configurations are studied to analyze the effects of individual traps on carrier recombination and base leakage currents. In npn transistors, deep traps (0.42 eV from the conduction band) dominate at low voltages, while shallow traps (0.17 eV from the conduction band) become prominent at higher voltages. Conversely, pnp transistors have base leakage current predominantly due to deep-level traps. The study observes a notable trend in trap density versus fluence, characterized by a linear relationship on a log-log scale. These insights into defect evolution under radiation conditions are crucial for optimizing semiconductor device reliability and performance in radiation-prone environments.

42 ENGINEERING↗
DOE OSTI2022

Vector-Matrix Multiplication Engine for Neuromorphic Computation with a CBRAM Crossbar Array [Slides]

The core function of many neural network algorithms is the dot product, or vector matrix multiply (VMM) operation. Crossbar arrays utilizing resistive memory elements can reduce computational energy in neural algorithms by up to five orders of magnitude compared to conventional CPUs. Moving data between a processor, SRAM, and DRAM dominates energy consumption. By utilizing analog operations to reduce data movement, resistive memory crossbars can enable processing of large amounts of data at lower energy than conventional memory architectures.

97 MATHEMATICS AND COMPUTING↗
NASA NTRS2011

Modeling the effects of hydrogen and dose rate sensitivity in CMOS and bipolar technologies

Low dose rate (LDR) and high dose rate (HDR) experiments on field-oxide-field-effect-transistors (FOXFETs) and gated lateral pnp (GLPNP) bipolar transistors indicate that there is a dose rate enhancement factor (EF) associated with radiation-induced degradation. This EF is also affect by the presence of hydrogen in the oxide. In this work, we developed a one dimensional (1-D) numerical calculations code to investigate the key mechanisms that describe the dose rate sensitivity and the effect of hydrogen on dose rate effects. We used a finite-difference methodology for the numerical calculations that allow for computing solutions for the densities of the mobile species as well as for the electrostatic potential at nodes contained within a mesh superimposed on the solution domain. Results from calculations of damage EF indicate that oxide thickness, distribution of hole traps and hole capture cross-section affect dose rate sensitivity. In addition, calculations show that molecular hydrogen cracking at positively charged defects may be a key reaction relating hydrogen and dose rate response. Comparison to experimental data on bipolar and CMOS devices results in good agreement with the dose rate calculations of interface trap buildup

Barnaby, Hugh↗
NASA NTRS2009

Irradiation with molecular hydrogen as an accelerated total dose hardness assurance test method for bipolar linear circuits

High dose rate irradiation with hydrogen stress is proposed as an accelerated total dose test method for bipolar linear circuits. The method is validated across process and circuit technologies with five parts that are commonly used in space: a comparator (LM193 from National Semi-conductor), a voltage regulator (HSYE-117 RH from Intersil), a voltage reference (LT1019 from Linear Technology), a JFET input op amp (OP42 from Analog Devices) and a temperature transducer (AD590 from Analog Devices). The testing technique could rapidly establish an upper bound to the low dose rate response of parts in space and help with the part selection process in the design phase of a mission. The technology dependence and the viability of this technique are qualitatively explored using a physical model describing the dose rate response and the effect of hydrogen in bipolar technologies. The model uses four core processes: 1) space charge effects, 2) free electron/hole pair recombination, hole-hydrogen defect reactions in the oxides and 4) proton depassivation of dangling bonds at the Si/SiO2 interface. Radiation hardness assurance implications are discussed.

Pease, Ron↗
NASA NTRS2009

Understanding how molecular hydrogen impacts the total dose and dose rate response of linear bipolar circuits

Recent Enhanced Low Dose Rate Sensitivity (ELDRS) investigations carried out by RLP Research, Arizona State University (ASU) and Jet Propulsion Laboratory (JPL) have shown significant differences in the degradation of bipolar micro-circuits with total dose in the presence of molecular hydrogen (H2) in packages. This has a significant impact on radiation hardness assurance and opens up opportunities to improve device performance. The general objectives of this program are to: 1. Determine the extent to which hydrogen contamination affects the total dose and dose rate response of linear bipolar circuits; 2. Develop a model that will enable the prediction of high dose rate (HDR) and low dose rate (LDR) response asymptotes and transition dose rates as a function of total dose, temperature, pressurized hydrogen, defect precursors, and other process dependent variables; 3. Explore the possibility of an accelerated hardness assurance method and possible hardening approaches; and 4. Extend the work to other technologies that have total dose response affected by hydrogen contamination.In this document, we xperimentally demonstrate with test transistors and circuits that hydrogen is correlated with ELDRS in bipolar linear circuits. We show that the amount of hydrogen determines: 1) the total dose response versus dose rate and 2) the transition dose rates between the high and low dose rate responses. The experimental results are supported with a steady state drift/diffusion analytical model as well as modeling calculations using COMSOL Multiphysics.

Pease, Ron↗