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216 results on '"Zhang, E. X."'

1. Temperature dependence of the low-frequency noise in AlGaN/GaN fin field effect transistors.

Author

Liu, T. K., Lee, H., Luo, X. Y., Zhang, E. X., Schrimpf, R. D., Rajan, S., and Fleetwood, D. M.

Subjects
MODULATION-doped field-effect transistors, FIELD-effect transistors, NOISE measurement, RADIATION tolerance, SPECTRAL energy distribution
Abstract

Low-frequency (LF) noise measurements are compared for Schottky-gate AlGaN/GaN heterostructure planar and fin field-effect transistors (FinFETs) as functions of gate voltage and measuring temperature. The noise of each device type is consistent with a carrier number fluctuation model. Similar effective defect-energy Eo distributions are derived for each of the two device architectures from measurements of excess drain-voltage noise-power spectral density vs temperature from 80 to 380 K. Defect- and/or impurity-related peaks are observed in the inferred energy distributions for Eo < 0.2 eV, Eo ≈ 0.45 eV, and Eo > 0.6 eV. Significant contributions to the LF noise are inferred for nitrogen vacancies and ON and FeGa impurity complexes. Ga dangling bonds at fin interfaces with gate metal are likely candidates for enhanced noise observed in FinFETs, relative to planar devices. Reducing the concentrations of these defects and impurity complexes should reduce the LF noise and enhance the performance, reliability, and radiation tolerance of GaN-based high electron mobility transistors. [ABSTRACT FROM AUTHOR]

Published
2024
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2. Proton-Irradiation-Immune Electronics Implemented with Two-Dimensional Charge-Density-Wave Devices

Author

Geremew, A., Kargar, F., Zhang, E. X., Zhao, S. E., Aytan, E., Bloodgood, M. A., Salguero, T. T., Rumyantsev, S., Fedoseyev, A., Fleetwood, D. M., and Balandin, A. A.

Subjects
Physics - Applied Physics, Condensed Matter - Mesoscale and Nanoscale Physics, Condensed Matter - Materials Science
Abstract

Proton radiation damage is an important failure mechanism for electronic devices in near-Earth orbits, deep space and high energy physics facilities. Protons can cause ionizing damage and atomic displacements, resulting in device degradation and malfunction. Shielding of electronics increases the weight and cost of the systems but does not eliminate destructive single events produced by energetic protons. Modern electronics based on semiconductors - even those specially designed for radiation hardness - remain highly susceptible to proton damage. Here we demonstrate that room temperature (RT) charge-density-wave (CDW) devices with quasi-two-dimensional (2D) 1T-TaS2 channels show remarkable immunity to bombardment with 1.8 MeV protons to a fluence of at least 10^14 H+cm^2. Current-voltage I-V characteristics of these 2D CDW devices do not change as a result of proton irradiation, in striking contrast to most conventional semiconductor devices or other 2D devices. Only negligible changes are found in the low-frequency noise spectra. The radiation immunity of these "all-metallic" CDW devices can be attributed to their two-terminal design, quasi-2D nature of the active channel, and high concentration of charge carriers in the utilized CDW phases. Such devices, capable of operating over a wide temperature range, can constitute a crucial segment of future electronics for space, particle accelerator and other radiation environments., Comment: 18 pages, 2 display items

Published
2019
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3. Low-frequency noise and defects in AlGaAs/InGaAs/GaAs pseudomorphic high-electron mobility transistors.

Author

Luo, X. Y., O'Hara, A., Li, X., Wang, P. F., Zhang, E. X., Schrimpf, R. D., Pantelides, S. T., and Fleetwood, D. M.

Subjects
TWO-dimensional electron gas, IMPURITY centers, INDIUM gallium arsenide, MODULATION-doped field-effect transistors, TRANSISTORS, NOISE
Abstract

Current–voltage characteristics and low-frequency (LF) noise of industrial-quality AlGaAs/InGaAs/GaAs pseudomorphic high-electron-mobility transistors are evaluated as a function of bias stress and temperature. A small positive shift of threshold voltage Vth and negligible degradation in peak transconductance GM are observed under ON-state bias conditions at elevated temperatures. The Vth measurements suggest activation of an acceptor-like defect or impurity center. The GM measurements demonstrate that newly activated defects are not located close enough to the two-dimensional electron gas to scatter carriers strongly. First-principles calculations and comparisons with previous work suggest that OAs impurity centers, other oxygen-related defects, isolated AsGa antisites, and dopant-based DX centers may contribute significantly to low-frequency (LF) noise in as-processed devices. LF noise is relatively unaffected by voltage stress at elevated temperatures, consistent with the small changes in Vth and peak GM. [ABSTRACT FROM AUTHOR]

Published
2024
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4. Total Ionizing Dose Effects on Threshold Switching in 1T-Tantalum Disulfide Charge-Density-Wave Devices

Author

Liu, G., Zhang, E. X., Liang, C. D., Bloodgood, M. A., Salguero, T. T., Fleetwood, D. M., and Balandin, A. A.

Subjects
Physics - Applied Physics, Condensed Matter - Mesoscale and Nanoscale Physics
Abstract

The 1T polytype of TaS2 exhibits voltage-triggered threshold switching as a result of a phase transition from nearly commensurate to incommensurate charge density wave states. Threshold switching, persistent above room temperature, can be utilized in a variety of electronic devices, e.g., voltage controlled oscillators. We evaluated the total-ionizing-dose response of thin film 1T-TaS2 at doses up to 1 Mrad(SiO2). The threshold voltage changed by less than 2% after irradiation, with persistent self-sustained oscillations observed through the full irradiation sequence. The radiation hardness is attributed to the high intrinsic carrier concentration of 1T-TaS2 in both of the phases that lead to threshold switching. These results suggest that charge density wave devices, implemented with thin films of 1T-TaS2, are promising for applications in high radiation environments., Comment: 4 pages; 4 figures

Published
2017
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6. Single-Event Effects in Heavy-Ion Irradiated 3kV SiC Charge-Balanced Power Devices

Author

Sengupta, A., primary, Ball, D. R., additional, Islam, S., additional, Senarath, A. S., additional, Sternberg, A. L., additional, Zhang, E. X., additional, Alles, M. L., additional, Osheroff, J. M., additional, Ghandi, R., additional, Jacob, B., additional, Goswami, S., additional, Hitchcock, C. W., additional, Hutson, J.M., additional, Reed, R. A., additional, Galloway, K. F., additional, Schrimpf, R. D., additional, and Witulski, A. F., additional

Published
2024
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7. Single-event burnout in homojunction GaN vertical PiN diodes with hybrid edge termination design.

Author

Senarath, A. S., Islam, S., Sengupta, A., McCurdy, M. W., Anderson, T., Jacobs, A., Kaplar, R., Ball, D. R., Zhang, E. X., Pantelides, S. T., Reed, R. A., Ebrish, M. A., Fleetwood, D. M., Caldwell, J. D., and Schrimpf, R. D.

Subjects
PIN diodes, GALLIUM nitride, LINEAR energy transfer, PLASMA diodes, ALPHA rays, ELECTRIC breakdown, BREAKDOWN voltage
Abstract

GaN devices play a major role in modern electronics, providing high-power handling, efficient high-frequency operation, and resilience in harsh environments. However, electric field crowding at the edge of the anode often limits its full potential, leading to single-event effects (SEEs) at lower bias voltages under heavy ion radiation. Here, we report on the performance of homojunction GaN vertical PiN diodes with a hybrid edge termination design under heavy ion irradiation, specifically, oxygen ions, chlorine ions, Cf-252 fission fragments, and alpha particles from an Am-241 source. The unique hybrid edge termination (HET) design provides better electric field management, preventing breakdown from occurring at the edge of the anode at lower voltages. The results of this study reveal that these devices exhibit excellent tolerance to 12-MeV oxygen and 16-MeV chlorine ions, owing to their low linear energy transfer (LET) and range in GaN. However, single-event burnout (SEB) is observed during the Cf-252 exposure at about 50% of the diodes' electrical breakdown voltage due to the presence of higher LET and longer-range ions. Optical and scanning electron microscopy (SEM) reveal that the damage that caused by SEB lies close to the center of these devices rather than the anode edge. Devices with junction termination extension (JTE) instead of HET edge termination also show similar SEB when irradiated with Cf-252 fission fragments. Physical damage due to SEB occurs at the edge of the anode for these devices. These comparative results show the benefits of HET for enhancing the resistance of GaN-based PiN diodes to heavy ion irradiation. [ABSTRACT FROM AUTHOR]

Published
2024
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10. Low-Energy Ion-Induced Single-Event Burnout in Gallium Oxide Schottky Diodes

Author

Cadena, R. M., primary, Ball, D. R., additional, Zhang, E. X., additional, Islam, S., additional, Senarath, A., additional, McCurdy, M. W., additional, Farzana, E., additional, Speck, J. S., additional, Karom, N., additional, O'Hara, A., additional, Tuttle, B. R., additional, Pantelides, S. T., additional, Witulski, A. F., additional, Galloway, K. F., additional, Alles, M. L., additional, Reed, R. A., additional, Fleetwood, D. M., additional, and Schrimpf, R. D., additional

Published
2023
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11. Single-Event Burnout in Vertical β-Ga₂O₃ Diodes With Pt/PtOₓ Schottky Contacts and High-k Field-Plate Dielectrics

Author

Islam, S., Senarath, A. S., Farzana, E., Ball, D. R., Sengupta, A., Hendricks, N. S., Bhattacharyya, A., Reed, R. A., Zhang, E. X., Speck, J. S., Fleetwood, D. M., and Schrimpf, R. D.

Abstract

Single-event burnout (SEB) is experimentally observed in structurally improved vertical Beta-gallium oxide ( $\beta $ -Ga2O3) Schottky barrier diodes (SBDs) with Pt/PtOx Schottky contacts and high-k field-plate (FP) dielectrics. These SBDs are resistant to alpha particle strikes up to the in-air reverse bias voltage of 475 V, but SEB-induced catastrophic failure is observed during Californium-252 (Cf-252) fission fragment exposure at 400 ± 20 V reverse bias. The SEB threshold in Cf-252 testing is improved in PtOx-contact SBDs with 4- $\mu \text{m}$ epitaxial layers and high-k FP dielectrics by ~30%, compared to previously reported results for Pt-contact SBDs with 10- $\mu \text{m}$ epitaxial layers. TCAD simulations show that ion-induced electric fields increase less in devices with FPs than in those without FPs.

Published
2024
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12. Defect and Impurity-Center Activation and Passivation in Irradiated AlGaN/GaN HEMTs

Author

Li, X., Wang, P. F., Zhao, X., Qiu, H., Gorchichko, M., McCurdy, M. W., Schrimpf, R. D., Zhang, E. X., and Fleetwood, D. M.

Abstract

Donor-like defects are activated and acceptor-like defects are passivated when commercial AlGaN/GaN high electron mobility transistors (HEMTs) are irradiated with 10-keV X-rays or 1.8-MeV protons at low fluence. Displacement-damage-induced creation of acceptor-like defects is observed at higher proton fluences. The dehydrogenation of FeGa-H and $\text{O}_{\mathrm {N}}$ -H substitutional impurities and generation of N-vacancy-related defects most likely account for the modest degradation of these devices at high proton fluences. Low-frequency (LF) noise measurements identify FeGa defects as prominent generation–recombination (G–R) centers in these devices. These results enable recalibration of the Dutta–Horn model of LF noise and increased insight into the defect identities and energy distributions in AlGaN/GaN HEMTs.

Published
2024
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18. Correlation of proton irradiation induced threshold voltage shifts to deep level traps in AlGaN/GaN heterostructures.

Author

Zhang, Z., Cardwell, D., Sasikumar, A., Kyle, E. C. H., Chen, J., Zhang, E. X., Fleetwood, D. M., Schrimpf, R. D., Speck, J. S., Arehart, A. R., and Ringel, S. A.

Subjects
ELECTRIC properties of aluminum gallium nitride, HETEROSTRUCTURES, PROTONS, IRRADIATION, THRESHOLD voltage, ION traps
Abstract

The impact of proton irradiation on the threshold voltage (VT) of AlGaN/GaN heterostructures is systematically investigated to enhance the understanding of a primary component of the degradation of irradiated high electron mobility transistors. The value of VT was found to increase monotonically as a function of 1.8MeV proton fluence in a sub-linear manner reaching 0.63V at a fluence of 1×1014 cm-2. Silvaco Atlas simulations of VT shifts caused by GaN buffer traps using experimentally measured introduction rates, and energy levels closely match the experimental results. Different buffer designs lead to different VT dependences on proton irradiation, confirming that deep, acceptorlike defects in the GaN buffer are primarily responsible for the observed VT shifts. The proton irradiation induced VT shifts are found to depend on the barrier thickness in a linear fashion; thus, scaling the barrier thickness could be an effective way to reduce such degradation. [ABSTRACT FROM AUTHOR]

Published
2016
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19. Thermal stability of deep level defects induced by high energy proton irradiation in n-type GaN.

Author

Zhang, Z., Farzana, E., Sun, W. Y., Chen, J., Zhang, E. X., Fleetwood, D. M., Schrimpf, R. D., McSkimming, B., Kyle, E. C. H., Speck, J. S., Arehart, A. R., and Ringel, S. A.

Subjects
GALLIUM nitride, PROTONS, THERMAL stability, IRRADIATION, ANNEALING of metals
Abstract

The impact of annealing of proton irradiation-induced defects in n-type GaN devices has been systematically investigated using deep level transient and optical spectroscopies. Moderate temperature annealing (>200-250 °C) causes significant reduction in the concentration of nearly all irradiation-induced traps. While the decreased concentration of previously identified N and Ga vacancy related levels at EC-0.13 eV, 0.16 eV, and 2.50 eV generally followed a first-order reaction model with activation energies matching theoretical values for NI and VGa diffusion, irradiation-induced traps at EC-0.72 eV, 1.25 eV, and 3.28 eV all decrease in concentration in a gradual manner, suggesting a more complex reduction mechanism. Slight increases in concentration are observed for the N-vacancy related levels at EC-0.20 eV and 0.25 eV, which may be due to the reconfiguration of other N-vacancy related defects. Finally, the observed reduction in concentrations of the states at EC-1.25 and EC-3.28 eV as a function of annealing temperature closely tracks the detailed recovery behavior of the background carrier concentration as a function of annealing temperature. As a result, it is suggested that these two levels are likely to be responsible for the underlying carrier compensation effect that causes the observation of carrier removal in proton-irradiated n-GaN. [ABSTRACT FROM AUTHOR]

Published
2015
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20. Gate Bias and Length Dependences of Total-Ionizing-Dose Effects in InGaAs FinFETs on Bulk Si

Author

Zhao, S. E., Bonaldo, S., Wang, P., Jiang, R., Gong, H., Zhang, E. X., Waldron, N., Kunert, B., Mitard, J., Collaert, N., Sioncke, S., Linten, D., Schrimpf, R. D., Reed, R. A., Gerardin, S., Paccagnella, A., and Fleetwood, D. M.

Subjects
total ionizing dose (TID), FinFETs, InGaAs, bulk Si, border trap, III–V, gate-length dependence, 1/ f noise, 1/ f noise, III–V, border trap, bulk Si, FinFETs, gate-length dependence, InGaAs, total ionizing dose (TID)
Published
2019

22. Exploiting SEU Data Analysis to Extract Fast SET Pulses

Author

Harrington, R. C., primary, Kauppila, J. S., additional, Maharrey, J. A., additional, Haeffner, T. D., additional, Zhang, E. X., additional, Ball, D. R., additional, Nsengiyumva, P., additional, Alles, M. L., additional, Bhuva, B. L., additional, and Massengill, L. W., additional

Published
2019
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24. Low-frequency noise and defects in copper and ruthenium resistors

Author

Fleetwood, D. M., primary, Beyne, S., additional, Jiang, R., additional, Zhao, S. E., additional, Wang, P., additional, Bonaldo, S., additional, McCurdy, M. W., additional, Tőkei, Zs., additional, DeWolf, I., additional, Croes, Kristof, additional, Zhang, E. X., additional, Alles, M. L., additional, Schrimpf, R. D., additional, Reed, R. A., additional, and Linten, D., additional

Published
2019
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25. Laser-Induced Single-Event Transients in Black Phosphorus MOSFETs

Author

Liang, C., primary, Ma, R., additional, Li, K., additional, Su, Y., additional, Gong, H., additional, Ryder, K. L., additional, Wang, P., additional, Sternberg, A. L., additional, Zhang, E. X., additional, Alles, M. L., additional, Reed, R. A., additional, Koester, S. J., additional, Fleetwood, D. M., additional, and Schrimpf, R. D., additional

Published
2019
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27. Dual-Interlocked Logic for Single-Event Transient Mitigation

Author

Maharrey, J. A., primary, Kauppila, J. S., additional, Harrington, R. C., additional, Nsengiyumva, P., additional, Ball, D. R., additional, Haeffner, T. D., additional, Zhang, E. X., additional, Bhuva, B. L., additional, Holman, W. T., additional, and Massengill, L. W., additional

Published
2018
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28. X-Ray and Proton Radiation Effects on 40 nm CMOS Physically Unclonable Function Devices

Author

Wang, P. F., primary, Zhang, E. X., additional, Chuang, K. H., additional, Liao, W., additional, Gong, H., additional, Wang, P., additional, Arutt, C. N., additional, Ni, K., additional, Mccurdy, M. W., additional, Verbauwhede, I., additional, Bury, E., additional, Linten, D., additional, Fleetwood, D. M., additional, Schrimpf, R. D., additional, and Reed, R. A., additional

Published
2018
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33. The Impact of Charge Collection Volume and Parasitic Capacitance on SEUs in SOI- and Bulk-FinFET D Flip-Flops

Author

Ball, D. R., primary, Alles, M. L., additional, Kauppila, J. S., additional, Harrington, R. C., additional, Maharrey, J. A., additional, Nsengiyumva, P., additional, Haeffner, T. D., additional, Rowe, J. D., additional, Sternberg, A. L., additional, Zhang, E. X., additional, Bhuva, B. L., additional, and Massengill, L. W., additional

Published
2018
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38. Memristive devices from ZnO nanowire bundles and meshes

Author

Puzyrev, Y. S., primary, Shen, X., additional, Zhang, C. X., additional, Hachtel, J., additional, Ni, K., additional, Choi, B. K., additional, Zhang, E.-X., additional, Ovchinnikov, O., additional, Schrimpf, R. D., additional, Fleetwood, D. M., additional, and Pantelides, S. T., additional

Published
2017
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42. Analysis of TID Process, Geometry, and Bias Condition Dependence in 14-nm FinFETs and Implications for RF and SRAM Performance

Author

King, M. P., primary, Wu, X., additional, Eller, M., additional, Samavedam, S., additional, Shaneyfelt, M. R., additional, Silva, A. I., additional, Draper, B. L., additional, Rice, W. C., additional, Meisenheimer, T. L., additional, Felix, J. A., additional, Zhang, E. X., additional, Haeffner, T. D., additional, Ball, D. R., additional, Shetler, K. J., additional, Alles, M. L., additional, Kauppila, J. S., additional, and Massengill, L. W., additional

Published
2017
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44. 1/f noise in GaN/AlGaN HEMTs

Author

Fleetwood, D. M., primary, Wang, P., additional, Chen, J., additional, Jiang, R., additional, Zhang, E. X., additional, McCurdy, M. W., additional, and Schrimpf, R. D., additional

Published
2016
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50. Heavy Ion SEU Test Data for 32nm SOI Flip-Flops

Author

Quinn, R. C., primary, Kauppila, J. S., additional, Loveless, T. D., additional, Maharrey, J. A., additional, Rowe, J. D., additional, McCurdy, M. W., additional, Zhang, E. X., additional, Alles, M. L., additional, Bhuva, B. L., additional, Reed, R. A., additional, Holman, W. T., additional, Bounasser, M., additional, Lilja, K., additional, and Massengill, L. W., additional

Published
2015
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