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Development characterization and modeling of a TaOx ReRAM for a neuromorphic accelerator

Marinella, Matthew J.; Mickel, Patrick R.; Lohn, Andrew L.; Hughart, David R.; Bondi, Robert J.; Mamaluy, Denis M.; Hjalmarson, Harold P.; Stevens, James E.; Decker, Seth D.; Apodaca, Roger A.; Evans, Brian R.; Aimone, James B.; Rothganger, Fredrick R.; James, Conrad D.; DeBenedictis, Erik

This report discusses aspects of neuromorphic computing and how it is used to model microsystems.

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TYPE Conference Poster YEAR 2014
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Detection and characterization of multi-filament evolution during resistive switching

Applied Physics Letters

Mickel, Patrick R.; Lohn, Andrew L.; Marinella, Matthew J.

We report resistive switching data in TaOx memristors displaying signatures of multi-filament switching modes and present a technique which enables the characterization of the evolution of multiple filaments within a single device during switching, including their temperature, heat flow, conductivity, and time evolving areas. Using a geometrically defined equivalent circuit, we resolve the individual current/voltage values of each filament and demonstrate that the switching curves of each filament collapse onto a common curve determined by the analytical steady-state resistive switching solution for filamentary switching. Finally, we discuss operational modes which may limit the formation of additional conducting filaments, potentially leading to increased device endurance. © 2014 AIP Publishing LLC.

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TYPE Journal Article YEAR 2014
ScopusOSTIDOI

Rutherford forward scattering and elastic recoil detection (RFSERD) as a method for characterizing ultra-thin films

Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms

Lohn, Andrew J.; Doyle, Barney L.; Stein, Gregory J.; Mickel, Patrick R.; Stevens, James E.; Marinella, Matthew J.

We present a novel ion beam analysis technique combining Rutherford forward scattering and elastic recoil detection (RFSERD) and demonstrate its ability to increase efficiency in determining stoichiometry in ultrathin (5-50 nm) films as compared to Rutherford backscattering. In the conventional forward geometries, scattering from the substrate overwhelms the signal from light atoms but in RFSERD, scattered ions from the substrate are ranged out while forward scattered ions and recoiled atoms from the thin film are simultaneously detected in a single detector. The technique is applied to tantalum oxide memristors but can be extended to a wide range of materials systems. © 2014 Published by Elsevier B.V.

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TYPE Journal Article YEAR 2014
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Emerging resistive switching memory technologies: Overview and current status

Proceedings - IEEE International Symposium on Circuits and Systems

Marinella, Matthew J.

Resistive memory technologies, in particular redox random access memory (ReRAM), are poised as one of the most prominent emerging memory categories to replace NAND flash and fill the important need for a Storage Class Memory (SCM). This is due to low switching energy, low current switching, high speed, outstanding endurance, scalability below 10 nm, and excellent back-end-of-line CMOS compatibility. Furthermore, the analog aspects of memristors have opened the door for many novel applications such as analog math accelerators and neuromorphic computers. This paper provides an overview of resistive memory technologies and their current status, with a focus on redox RAM (ReRAM). © 2014 IEEE.

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TYPE Conference YEAR 2014
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A comprehensive approach to decipher biological computation to achieve next generation high-performance exascale computing

Howell, Jamie D.; Lohn, Andrew L.; Marinella, Matthew J.; Baca, Michael J.; Finnegan, Patrick S.; Wolfley, Steven L.; Dagel, Daryl D.; Spahn, Olga B.; Harper, Jason C.; Pohl, Kenneth R.; Mickel, Patrick R.

The human brain (volume=1200cm3) consumes 20W and is capable of performing > 10^16 operations/s. Current supercomputer technology has reached 1015 operations/s, yet it requires 1500m^3 and 3MW, giving the brain a 10^12 advantage in operations/s/W/cm^3. Thus, to reach exascale computation, two achievements are required: 1) improved understanding of computation in biological tissue, and 2) a paradigm shift towards neuromorphic computing where hardware circuits mimic properties of neural tissue. To address 1), we will interrogate corticostriatal networks in mouse brain tissue slices, specifically with regard to their frequency filtering capabilities as a function of input stimulus. To address 2), we will instantiate biological computing characteristics such as multi-bit storage into hardware devices with future computational and memory applications. Resistive memory devices will be modeled, designed, and fabricated in the MESA facility in consultation with our internal and external collaborators.

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TYPE SAND Report YEAR 2013
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Electrical conductivity in oxygen-deficient phases of transition metal oxides from first-principles calculations

Desjarlais, Michael P.; Thompson, Aidan P.; Brennecka, Geoffrey L.; Marinella, Matthew J.

Density-functional theory calculations, ab-initio molecular dynamics, and the Kubo-Greenwood formula are applied to predict electrical conductivity in Ta2Ox (0 x 5) as a function of composition, phase, and temperature, where additional focus is given to various oxidation states of the O monovacancy (VOn; n=0,1+,2+). Our calculations of DC conductivity at 300K agree well with experimental measurements taken on Ta2Ox thin films and bulk Ta2O5 powder-sintered pellets, although simulation accuracy can be improved for the most insulating, stoichiometric compositions. Our conductivity calculations and further interrogation of the O-deficient Ta2O5 electronic structure provide further theoretical basis to substantiate VO0 as a donor dopant in Ta2O5 and other metal oxides. Furthermore, this dopant-like behavior appears specific to neutral VO cases in both Ta2O5 and TiO2 and was not observed in other oxidation states. This suggests that reduction and oxidation reactions may effectively act as donor activation and deactivation mechanisms, respectively, for VO0 in transition metal oxides.

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TYPE SAND Report YEAR 2013
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A CMOS Compatible, Forming Free TaOx ReRAM

ECS Transactions (Online)

Stevens, James E.; Mickel, Patrick R.; Hughart, David R.; Marinella, Matthew J.

Resistive random access memory (ReRAM) has become a promising candidate for next-generation high-performance non-volatile memory that operates by electrically tuning resistance states via modulating vacancy concentrations. Here, we demonstrate a wafer-scale process for resistive switching in tantalum oxide that is completely CMOS compatible. The resulting devices are forming-free and with greater than 1x105 cycle endurance.

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TYPE Journal Article YEAR 2013
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GaN-based wide-bandgap power switching devices: From atoms to the grid

ECS Transactions

Atcitty, Stanley A.; Kaplar, Robert K.; DasGupta, Sandeepan D.; Marinella, Matthew J.; Armstrong, Andrew A.; Biedermann, Laura B.; Sun, Min; Palacios, Tomas; Smith, Mark A.

Emerging semiconductor switches based on the wide-bandgap semiconductor GaN have the potential to significantly improve the efficiency of portable power applications such as transportable energy storage. Such applications are likely to become more widespread as renewables such as wind and solar continue to come on-line. However, the long-term reliability of GaN-based power devices is relatively unexplored. In this paper, we describe joint work between Sandia National Laboratories and MIT on highvoltage AlGaN/GaN high electron mobility transistors. It is observed that the nature of current collapse is a strong function of bias conditions as well as device design, where factors such as Al composition in the barrier layer and surface passivation play a large role. Thermal and optical recovery experiments are performed to ascertain the nature of charge trapping in the device. Additionally, Kelvin-force microscopy measurements are used to evaluate the surface potential within the device. © The Electrochemical Society.

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TYPE Conference YEAR 2013
ScopusOSTI

Slow detrapping transients due to gate and drain bias stress in high breakdown voltage AlGaN/GaN HEMTs

IEEE Transactions on Electron Devices

Dasgupta, Sandeepan; Sun, Min; Armstrong, Andrew A.; Kaplar, Robert K.; Marinella, Matthew J.; Stanley, James B.; Atcitty, Stanley A.; Palacios, Tomas

Charge trapping and slow (from 10 s to > 1000 s) detrapping in AlGaN/GaN high electron mobility transistors (HEMTs) designed for high breakdown voltages (> 1500 V) is studied through a combination of electrical, thermal, and optical methods to identify the impact of Al molefraction and passivation on trapping. Trapping due to 5-10 V drain bias stress in the on-state (V gs = 0) is found to have significantly slower recovery, compared with trapping in the off-state (V gs < V th, V ds = 0). Two different trapping components, i.e., TG1 (E a = 0.6 eV) and TG2 (with negligible temperature dependence), in AlGaN dominate under gate bias stress in the off-state. Al 0.15 Ga 0.85N shows much more vulnerability to trapping under gate stress in the absence of passivation than does AlGaN with a higher Al mole fraction. Under large drain bias, trapping is dominated by a much deeper trap TD. Detrapping under monochromatic light shows TD to have E a ≈ 1.65 eV. Carbon doping in the buffer is shown to introduce threshold voltage shifts, unlike any of the other traps. © 2012 IEEE.

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TYPE Journal Article YEAR 2012
ScopusOSTIDOI

PV inverter performance and reliability: What is the role of the bus capacitor?

IEEE Journal of Photovoltaics

Kaplar, Robert K.; Marinella, Matthew J.; Granata, Jennifer E.

In order to elucidate how the degradation of individual components affects the state of the photovoltaic inverter as a whole, we have carried out SPICE simulations to investigate the voltage and current ripple on the DC bus. The bus capacitor is generally considered to be among the least reliable components of the system, so we have simulated how the degradation of bus capacitors affects the AC ripple at the terminals of the PV module. Degradation-induced ripple leads to an increased degradation rate in a positive feedback cycle. Additionally, laboratory experiments are being carried out to ascertain the reliability of metallized thin film capacitors. By understanding the degradation mechanisms and their effects on the inverter as a system, steps can be made to more effectively replace marginal components with more reliable ones, increasing the lifetime and efficiency of the inverter and decreasing its cost per watt towards the US Department of Energy goals.

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TYPE Journal Article YEAR 2012
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Sub-bandgap light-induced carrier generation at room temperature in silicon carbide MOS capacitors

Materials Science Forum

DasGupta, Sandeepan D.; Armstrong, Andrew A.; Kaplar, Robert K.; Marinella, Matthew J.; Brock, Reinhard; Smith, Mark A.; Atcitty, Stanley A.

Carrier generation characteristics in n-type substrate SiC MOS capacitors induced by sub-bandgap energy light are reported. The generation rate is high enough to create an inversion layer in ∼20 minutes with monochromatic light (front side illumination) of energy 2.1 eV (intensity ∼5×10 16 cm-2s-1) in 4H-SiC for electric fields smaller than 1 MV/cm. Generation and recovery results strongly indicate involvement of a metastable defect whose efficiency as a generation center increases under hole-rich and decreases under electron-rich conditions. The generation dependence on bias history and light energy shows the defect to have properties consistent with the metastable silicon vacancy / carbon vacancy-antisite complex (VSi/Vc-CSi). © (2012) Trans Tech Publications.

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TYPE Conference YEAR 2012
ScopusOSTI

Gap analysis towards a design qualification standard development for grid-connected photovoltaic inverters

Conference Record of the IEEE Photovoltaic Specialists Conference

Venkataramanan, Sai B.; Ayyanar, Raja; Maracas, George; Tamizhmani, Govindasamy; Marinella, Matthew J.; Granata, Jennifer E.

A dedicated design qualification standard for PV inverters does not exist. Development of a well-accepted design qualification standard, specifically for PV inverters will significantly improve the reliability and performance of inverters. The existing standards for PV inverters such as ANSI/UL 1741 and IEC 62109-1 primarily focus on safety of PV inverters. The IEC 62093 discusses inverter qualification but it includes all the BOS components. There are other general standards for distributed generators including the IEEE 1547 series of standards which cover major concerns like utility integration but they are not dedicated to PV inverters and are not written from a design qualification point of view. In this paper some of the potential requirements for a design qualification standard for PV inverters are addressed. The missing links in existing PV inverter related standards are identified and with the IEC 62093 as a guideline, the possible inclusions in the framework for a dedicated design qualification standard of PV inverter are discussed. Some of the key missing links are related to electric stress tests. Hence, a method to adapt the existing surge withstand test standards for use in design qualification standard of PV inverter is presented. © 2011 IEEE.

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TYPE Conference YEAR 2011
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Sub-bandgap light-induced carrier generation at room temperature in 4H-SiC metal oxide semiconductor capacitors

Applied Physics Letters

Dasgupta, Sandeepan; Armstrong, Andrew A.; Kaplar, Robert K.; Marinella, Matthew J.; Brock, Reinhard; Smith, Mark A.; Atcitty, Stanley A.

Carrier generation characteristics in n-type substrate silicon carbide (SiC) metal oxide semiconductor capacitors induced by sub-bandgap energy light are reported. The generation rate is high enough to create an inversion layer in approximately 20 min with monochromatic front side illumination of energy 2.1 eV in 4H-SiC for electric fields less than 1 MV/cm. Generation and recovery results strongly indicate involvement of a metastable defect whose efficiency as a generation center increases under hole-rich and decreases under electron-rich conditions. The generation dependence on bias history and light energy shows the defect to have properties consistent with the metastable silicon vacancy/carbon vacancy-antisite complex (VSi/Vc-C Si). © 2011 American Institute of Physics.

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TYPE Journal Article YEAR 2011
ScopusOSTIDOI

Stress testing on silicon carbide electronic devices for prognostics and health management

Marinella, Matthew J.; Smith, Mark A.; Atcitty, Stanley A.

Power conversion systems for energy storage and other distributed energy resource applications are among the drivers of the important role that power electronics plays in providing reliable electricity. Wide band gap semiconductors such as silicon carbide (SiC) and gallium nitride (GaN) will help increase the performance and efficiency of power electronic equipment while condition monitoring (CM) and prognostics and health management (PHM) will increase the operational availability of the equipment and thereby make it more cost effective. Voltage and/or temperature stress testing were performed on a number of SiC devices in order to accelerate failure modes and to identify measureable shifts in electrical characteristics which may provide early indication of those failures. Those shifts can be interpreted and modeled to provide prognostic signatures for use in CM and/or PHM. Such experiments will also lead to a deeper understanding of basic device physics and the degradation mechanisms behind failure.

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TYPE SAND Report YEAR 2011
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Power electronics reliability

Smith, Mark A.; Kaplar, Robert K.; Marinella, Matthew J.; Stanley, James B.

The project's goals are: (1) use experiments and modeling to investigate and characterize stress-related failure modes of post-silicon power electronic (PE) devices such as silicon carbide (SiC) and gallium nitride (GaN) switches; and (2) seek opportunities for condition monitoring (CM) and prognostics and health management (PHM) to further enhance the reliability of power electronics devices and equipment. CM - detect anomalies and diagnose problems that require maintenance. PHM - track damage growth, predict time to failure, and manage subsequent maintenance and operations in such a way to optimize overall system utility against cost. The benefits of CM/PHM are: (1) operate power conversion systems in ways that will preclude predicted failures; (2) reduce unscheduled downtime and thereby reduce costs; and (3) pioneering reliability in SiC and GaN.

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TYPE Conference YEAR 2010
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Results 201–342 of 342
Results 201–342 of 342