Outputs (42)

Microstructural Response of Highly Porous Sintered Nano-silver Particle Die Attachments to Thermomechanical Cycling (2024)
Journal Article
Agyakwa, P. A., Robertson, S., Dai, J., Mouawad, B., Zhou, Z., Liu, C., & Johnson, C. M. (2024). Microstructural Response of Highly Porous Sintered Nano-silver Particle Die Attachments to Thermomechanical Cycling. Journal of Electronic Materials, 53, 1374–1398. https://doi.org/10.1007/s11664-023-10870-4

This paper deals with the performance of sintered nano-silver bonds used as wide-bandgap power module die attachment technology. The paper specifically explores the fine-scale microstructures of highly porous sintered attachments under power cycling... Read More about Microstructural Response of Highly Porous Sintered Nano-silver Particle Die Attachments to Thermomechanical Cycling.

Development and Validation of a Smart Architecture for Thyristor Valves (2023)
Journal Article
Sala, G., De Bonis, G., Costabeber, A., Tani, A., Johnson, C. M., & Clare, J. C. (2023). Development and Validation of a Smart Architecture for Thyristor Valves. IEEE Journal of Emerging and Selected Topics in Power Electronics, 11(4), 4068-4076. https://doi.org/10.1109/JESTPE.2023.3262344

A high voltage thyristor converter is realized by many valve sections, whose volume is approximately occupied for only the 10% by thyristors and for the 10% by the relevant gate drivers. The remaining 80% is taken by passive auxiliary circuits, neede... Read More about Development and Validation of a Smart Architecture for Thyristor Valves.

Reliability and Characterization of Nanosilver Joints Prepared by a Time-Reduced Sintering Process (2021)
Journal Article
Dai, J., Li, J., Agyakwa, P., Corfield, M., & Johnson, C. M. (2021). Reliability and Characterization of Nanosilver Joints Prepared by a Time-Reduced Sintering Process. IEEE Transactions on Device and Materials Reliability, 21(4), 536-543. https://doi.org/10.1109/TDMR.2021.3118323

This study investigates the power cycling reliability of nanosilver sintered joints formed by a time-reduced sintering process, designed for use on a die bonder. A range of sintering parameters, reflecting different levels of manufacturability, were... Read More about Reliability and Characterization of Nanosilver Joints Prepared by a Time-Reduced Sintering Process.

A GaN-HEMT Compact Model Including Dynamic RDSon Effect for Power Electronics Converters (2021)
Journal Article
Li, K., Evans, P. L., Johnson, C. M., Videt, A., & Idir, N. (2021). A GaN-HEMT Compact Model Including Dynamic RDSon Effect for Power Electronics Converters. Energies, 14(8), Article 2092. https://doi.org/10.3390/en14082092

In order to model GaN-HEMT switching transients and determine power losses, a compact model including dynamic RDSon effect is proposed herein. The model includes mathematical equations to represent device static and capacitance-voltage characteristic... Read More about A GaN-HEMT Compact Model Including Dynamic RDSon Effect for Power Electronics Converters.

Multi?frequency averaging (MFA) model of a generic electric vehicle powertrain suitable under variable frequency of averaging developed for remote operability (2020)
Journal Article
Sen, S., Evans, P. L., & Johnson, C. M. (2020). Multi?frequency averaging (MFA) model of a generic electric vehicle powertrain suitable under variable frequency of averaging developed for remote operability. IET Electrical Systems in Transportation, 10(3), 268-274. https://doi.org/10.1049/iet-est.2019.0043

© The Institution of Engineering and Technology 2020. Geographically distributed hardware-in-the-loop (HIL) testing has the potential to allow hybrid vehicle powertrain components (battery, motor drive, and engine) to be developed at geographically r... Read More about Multi?frequency averaging (MFA) model of a generic electric vehicle powertrain suitable under variable frequency of averaging developed for remote operability.

Accurate Measurement of Dynamic ON-state Resistance of GaN Devices under Reverse and Forward Conduction in High Frequency Power Converter (2020)
Journal Article
Li, K., Videt, A., Idir, N., Evans, P., & Johnson, M. (2020). Accurate Measurement of Dynamic ON-state Resistance of GaN Devices under Reverse and Forward Conduction in High Frequency Power Converter. IEEE Transactions on Power Electronics, 35(9), 9652-9662. https://doi.org/10.1109/TPEL.2019.2961604

Because of trapped charges in GaN transistor structure, device dynamic ON-state resistance RDSon is increased when it is operated in high frequency switched power converters, in which device is possibly operated by zero voltage switching (ZVS) to red... Read More about Accurate Measurement of Dynamic ON-state Resistance of GaN Devices under Reverse and Forward Conduction in High Frequency Power Converter.

10-kV SiC MOSFET Power Module With Reduced Common-Mode Noise and Electric Field (2019)
Journal Article
DiMarino, C. M., Mouawad, B., Johnson, C. M., Boroyevich, D., & Burgos, R. (2020). 10-kV SiC MOSFET Power Module With Reduced Common-Mode Noise and Electric Field. IEEE Transactions on Power Electronics, 35(6), 6050-6060. https://doi.org/10.1109/tpel.2019.2952633

The advancement of silicon carbide (SiC) power devices with voltage ratings exceeding 10 kV is expected to revolutionize medium- and high-voltage systems. However, present power module packages are limiting the performance of these unique switches. T... Read More about 10-kV SiC MOSFET Power Module With Reduced Common-Mode Noise and Electric Field.

Design and Experimental Validation of a Wire-Bond-Less 10-kV SiC MOSFET Power Module (2019)
Journal Article
DiMarino, C., Mouawad, B., Johnson, C. M., Wang, M., Tan, Y., Lu, G., …Burgos, R. (2020). Design and Experimental Validation of a Wire-Bond-Less 10-kV SiC MOSFET Power Module. IEEE Journal of Emerging and Selected Topics in Power Electronics, 8(1), 381-394. https://doi.org/10.1109/jestpe.2019.2944138

Wide bandgap (WBG) power devices with voltage ratings exceeding 10 kV have the potential to revolutionize medium-and high-voltage systems due to their high-speed switching and lower ON-state losses. However, the present power module packages are limi... Read More about Design and Experimental Validation of a Wire-Bond-Less 10-kV SiC MOSFET Power Module.

Three‐dimensional damage morphologies of thermomechanically deformed sintered nanosilver die attachments for power electronics modules (2019)
Journal Article
Agyakwa, P., Dai, J., Li, J., Mouawad, B., Yang, L., Corfield, M., & Johnson, C. (2019). Three‐dimensional damage morphologies of thermomechanically deformed sintered nanosilver die attachments for power electronics modules. Journal of Microscopy, 277(3), 140-153. https://doi.org/10.1111/jmi.12803

© 2019 The Authors. Journal of Microscopy published by John Wiley & Sons Ltd on behalf of Royal Microscopical Society. A time-lapse study of thermomechanical fatigue damage has been undertaken using three-dimensional X-ray computer tomography. Morp... Read More about Three‐dimensional damage morphologies of thermomechanically deformed sintered nanosilver die attachments for power electronics modules.

IEEE ITRW working group position paper: packaging and integration: unlocking the full potential of wide-bandgap devices (2018)
Journal Article
Johnson, M., Wilson, P. R., Empringham, L., & De Lillo, L. (2018). IEEE ITRW working group position paper: packaging and integration: unlocking the full potential of wide-bandgap devices. IEEE Power Electronics Magazine, 5(2), 26-33. https://doi.org/10.1109/mpel.2018.2822246

The International Technology Roadmap for Wide-Bandgap Power Semiconductors (ITRW) has four distinct technical working groups, each providing its own perspective on the technology and industrial drivers for the adoption of wide-bandgap (WBG) power sem... Read More about IEEE ITRW working group position paper: packaging and integration: unlocking the full potential of wide-bandgap devices.

Comparative Thermal and Structural Characterization of Sintered Nano-Silver and High-Lead Solder Die Attachments During Power Cycling (2018)
Journal Article
Dai, J., Li, J., Agyakwa, P., Corfield, M., & Johnson, C. M. (2018). Comparative Thermal and Structural Characterization of Sintered Nano-Silver and High-Lead Solder Die Attachments During Power Cycling. IEEE Transactions on Device and Materials Reliability, 18(2), 256-265. https://doi.org/10.1109/TDMR.2018.2825386

13.5 mm × 13.5 mm sintered nano-silver attachments for power devices onto AlN substrates were prepared at 250 ºC and a pressure of 10MPa for 5 minutes and compared with Pb5Sn solder joint die attachments under constant current power cycling with an i... Read More about Comparative Thermal and Structural Characterization of Sintered Nano-Silver and High-Lead Solder Die Attachments During Power Cycling.

Comparison of power cycling reliability of flexible PCB interconnect smaller/thinner and larger/thicker power devices with topside Sn-3.5Ag solder joints (2018)
Journal Article
Li, J., Dai, J., & Johnson, C. M. (2018). Comparison of power cycling reliability of flexible PCB interconnect smaller/thinner and larger/thicker power devices with topside Sn-3.5Ag solder joints. Microelectronics Reliability, 84, 55-65. https://doi.org/10.1016/j.microrel.2018.03.013

The power cycling reliability of flexible printed circuit board (PCB) interconnect smaller/thinner (ST) 9.5 mm × 5.5 mm × 0.07 mm and larger/thicker (LT) 13.5 mm × 13.5 mm × 0.5 mm single Si diode samples have been studied. With the assumption of cre... Read More about Comparison of power cycling reliability of flexible PCB interconnect smaller/thinner and larger/thicker power devices with topside Sn-3.5Ag solder joints.

Electrical Performance and Reliability Characterization of a SiC MOSFET Power Module With Embedded Decoupling Capacitors (2018)
Journal Article
O Brien, J., Yang, L., Li, K., Dai, J., Corfield, M., Harris, A., …Johnson, C. M. (2018). Electrical Performance and Reliability Characterization of a SiC MOSFET Power Module With Embedded Decoupling Capacitors. IEEE Transactions on Power Electronics, 33(12), 10594-10601. https://doi.org/10.1109/TPEL.2018.2809923

Integration of decoupling capacitors in SiC MOSFET modules is an advanced solution to mitigate the effect of parasitic inductance induced by module assembly interconnects. In this paper, the switching transient behavior is reported for a 1.2kV SiC MO... Read More about Electrical Performance and Reliability Characterization of a SiC MOSFET Power Module With Embedded Decoupling Capacitors.

Improved Reliability of Planar Power Interconnect With Ceramic-Based Structure (2017)
Journal Article
Zhang, H., Li, J., Dai, J., Corfield, M., Liu, X., Liu, Y., …Johnson, C. M. (2018). Improved Reliability of Planar Power Interconnect With Ceramic-Based Structure. IEEE Journal of Emerging and Selected Topics in Power Electronics, 6(1), 175-187. https://doi.org/10.1109/jestpe.2017.2758901

This paper proposes an advanced Si3N4 ceramic-based structure with through vias designed and filled with brazing alloy as a reliable interconnect solution in planar power modules. Finite element (FE) modeling and simulation were first used to predict... Read More about Improved Reliability of Planar Power Interconnect With Ceramic-Based Structure.

Time-Efficient Sintering Processes to Attach Power Devices Using Nanosilver Dry Film (2017)
Journal Article
Dai, J., Li, J., Agyakwa, P., & Johnson, C. M. (2017). Time-Efficient Sintering Processes to Attach Power Devices Using Nanosilver Dry Film. Journal of Microelectronics and Electronic Packaging, 14(4), 140-149. https://doi.org/10.4071/imaps.521776

Pressure-assisted sintering processes to attach power devices using wet nanosilver pastes with time scales of minutes to a few hours have been widely reported. This paper presents our work on time-efficient sintering, using nanosilver dry film and an... Read More about Time-Efficient Sintering Processes to Attach Power Devices Using Nanosilver Dry Film.

Characterisation and modelling of gallium nitride power semiconductor devices dynamic on-state resistance (2017)
Journal Article
Li, K., Evans, P., & Johnson, M. (2018). Characterisation and modelling of gallium nitride power semiconductor devices dynamic on-state resistance. IEEE Transactions on Power Electronics, 33(6), 5262 - 5273. https://doi.org/10.1109/TPEL.2017.2730260

GaN-HEMTs suffer from trapping effects which increases device ON-state resistance (RDS(on)) above its theoretical value. This increase is a function of the applied DC bias when the device is in its OFF state, and the time which the device is biased f... Read More about Characterisation and modelling of gallium nitride power semiconductor devices dynamic on-state resistance.

SiC/GaN power semiconductor devices: a theoretical comparison and experimental evaluation under different switching conditions (2017)
Journal Article
Li, K., Evans, P., & Johnson, M. (in press). SiC/GaN power semiconductor devices: a theoretical comparison and experimental evaluation under different switching conditions. IET Electrical Systems in Transportation, https://doi.org/10.1049/iet-est.2017.0022

The conduction and switching losses of SiC and GaN power transistors are compared in this paper. Voltage rating of commercial GaN power transistors is less than 650V while that of SiC power transistors is less than 1200V. The paper begins with a theo... Read More about SiC/GaN power semiconductor devices: a theoretical comparison and experimental evaluation under different switching conditions.

Time-efficient sintering processes to attach power devices using nanosilver dry film (2017)
Journal Article
Dai, J., Li, J., Agyakwa, P., & Mark Johnson, C. (2017). Time-efficient sintering processes to attach power devices using nanosilver dry film. Additional Conferences (Device Packaging, HiTEC, HiTEN, & CICMT), 2017(HiTEN), 000207–000212. https://doi.org/10.4071/2380-4491.2017.hiten.207

Pressure-assisted sintering processes to attach power devices using wet nanosilver pastes with time scales of minutes to a few hours have been widely reported. This paper presents our work on time-efficient sintering, using nanosilver dry film and an... Read More about Time-efficient sintering processes to attach power devices using nanosilver dry film.

A Physical RC Network Model for Electrothermal Analysis of a Multichip SiC Power Module (2017)
Journal Article
Li, J., Castellazzi, A., Eleffendi, M. A., Gurpinar, E., Johnson, C. M., & Mills, L. (2018). A Physical RC Network Model for Electrothermal Analysis of a Multichip SiC Power Module. IEEE Transactions on Power Electronics, 33(3), 2494-2508. https://doi.org/10.1109/TPEL.2017.2697959

© 2017 IEEE. This paper is concerned with the thermal models which can physically reflect the heat-flow paths in a lightweight three-phase half-bridge two-level SiC power module with six MOSFETs and can be used for coupled electrothermal simulation.... Read More about A Physical RC Network Model for Electrothermal Analysis of a Multichip SiC Power Module.

Interconnect materials enabling IGBT modules to achieve stable short circuit failure behavior (2017)
Journal Article
Li, J., Yaqub, I., Corfield, M., & Johnson, C. M. (2017). Interconnect materials enabling IGBT modules to achieve stable short circuit failure behavior. IEEE Transactions on Components, Packaging, and Manufacturing Technology, 7(5), 734-744. https://doi.org/10.1109/TCPMT.2017.2683202

Insulated gate bipolar transistor (IGBT) modules, which can fail to stable short-circuit mode, have major applications in electricity network-related fields. Sn-3.5Ag solder joints and sintered Ag joints for the die attachment and Mo, Cu, Sn-3.5Ag, A... Read More about Interconnect materials enabling IGBT modules to achieve stable short circuit failure behavior.

In-Service Diagnostics for Wire-Bond Lift-off and Solder Fatigue of Power Semiconductor Packages (2017)
Journal Article
Eleffendi, M. A., & Johnson, C. M. (2017). In-Service Diagnostics for Wire-Bond Lift-off and Solder Fatigue of Power Semiconductor Packages. IEEE Transactions on Power Electronics, 32(9), 7187-7198. https://doi.org/10.1109/TPEL.2016.2628705

Wire-bond lift-off and Solder fatigue are degradation mechanisms that dominate the lifetime of power semiconductor packages. Although their lifetime is commonly estimated at the design stage, based on mission profiles and Physics-of-Failure models, t... Read More about In-Service Diagnostics for Wire-Bond Lift-off and Solder Fatigue of Power Semiconductor Packages.

Damage Evolution in Al Wire Bonds Subjected to a Junction Temperature Fluctuation of 30K (2016)
Journal Article
Agyakwa, P., Yang, L., Arjmand, E., Evans, P., Corfield, M., & Johnson, C. M. (2016). Damage Evolution in Al Wire Bonds Subjected to a Junction Temperature Fluctuation of 30K. Journal of Electronic Materials, 45, 3659-3672. https://doi.org/10.1007/s11664-016-4519-0

© 2016, The Author(s). Ultrasonically bonded heavy Al wires subjected to a small junction temperature fluctuation under power cycling from 40°C to 70°C were investigated using a non-destructive three-dimensional (3-D) x-ray tomography evaluation appr... Read More about Damage Evolution in Al Wire Bonds Subjected to a Junction Temperature Fluctuation of 30K.

Predicting Lifetime of Thick Al Wire Bonds Using Signals Obtained From Ultrasonic Generator (2016)
Journal Article
Arjmand, E., Agyakwa, P., Corfield, M., Li, J., & Johnson, C. M. (2016). Predicting Lifetime of Thick Al Wire Bonds Using Signals Obtained From Ultrasonic Generator. IEEE Transactions on Components, Packaging, and Manufacturing Technology, 6(5), 814-821. https://doi.org/10.1109/TCPMT.2016.2543001

Routine monitoring of the wire bonding process requires real-time evaluation and control of wire bond quality. In this paper, we present a nondestructive technique for detecting bond quality by the application of a semisupervised classification algor... Read More about Predicting Lifetime of Thick Al Wire Bonds Using Signals Obtained From Ultrasonic Generator.

Integrated motor drives: state of the art and future trends (2016)
Journal Article
Abebe, R., Vakil, G., Lo Calzo, G., Cox, T., Lambert, S., Johnson, C. M., …Mecrow, B. (2016). Integrated motor drives: state of the art and future trends. IET Electric Power Applications, 10(8), 757-771. https://doi.org/10.1049/iet-epa.2015.0506

With increased need for high power density, high efficiency and high temperature capabilities in aerospace and automotive applications, integrated motor drives (IMD) offers a potential solution. However, close physical integration of the converter an... Read More about Integrated motor drives: state of the art and future trends.

Hybrid HVDC circuit breaker with self-powered gate drives (2016)
Journal Article
Effah, F. B., Watson, A. J., Ji, C., Amankwah, E. K., Johnson, C. M., Davidson, C., & Clare, J. C. (2016). Hybrid HVDC circuit breaker with self-powered gate drives. IET Power Electronics, 9(2), 228-236. https://doi.org/10.1049/iet-pel.2015.0531

The ever increasing electric power demand and the advent of renewable energy sources have revived the interest in high-voltage direct current (HVDC) multi-terminal networks. However, the absence of a suitable circuit breaker or fault tolerant VSC st... Read More about Hybrid HVDC circuit breaker with self-powered gate drives.

Real-time deterministic power flow control through dispatch of distributed energy resources (2015)
Journal Article
Fazeli, A., Sumner, M., Johnson, C. M., & Christopher, E. (2015). Real-time deterministic power flow control through dispatch of distributed energy resources. IET Generation, Transmission and Distribution, 9(16), https://doi.org/10.1049/iet-gtd.2015.0182

Integration of intermittent renewable resources and mass electrification of heat and transport into the existing electricity network, with limited network asset reinforcement requires incorporation of intelligence in form of active management of flex... Read More about Real-time deterministic power flow control through dispatch of distributed energy resources.

Dependence of overcurrent failure modes of IGBT modules on interconnect technologies (2015)
Journal Article
Yaqub, I., Li, J., & Johnson, C. M. (2015). Dependence of overcurrent failure modes of IGBT modules on interconnect technologies. Microelectronics Reliability, 55(12), 2596-2605. https://doi.org/10.1016/j.microrel.2015.09.020

Insulated gate bipolar transistor (IGBT) modules which can fail to short circuit mode have great of applications in electricity network related fields. Single IGBT samples have been constructed with the standard Al wire bonding, flexible printed circ... Read More about Dependence of overcurrent failure modes of IGBT modules on interconnect technologies.

Design Tools for Rapid Multidomain Virtual Prototyping of Power Electronic Systems (2015)
Journal Article
Evans, P. L., Castellazzi, A., & Johnson, C. M. (2016). Design Tools for Rapid Multidomain Virtual Prototyping of Power Electronic Systems. IEEE Transactions on Power Electronics, 31(3), 2443-2455. https://doi.org/10.1109/TPEL.2015.2437793

The need for multidisciplinary virtual prototyping in power electronics has been well established, however, design tools capable of facilitating a rapid iterative virtual design process do not exist. A key challenge in developing such tools is identi... Read More about Design Tools for Rapid Multidomain Virtual Prototyping of Power Electronic Systems.

Application of Kalman Filter to Estimate Junction Temperature in IGBT Power Modules (2015)
Journal Article
Eleffendi, M. A., & Johnson, C. M. (2016). Application of Kalman Filter to Estimate Junction Temperature in IGBT Power Modules. IEEE Transactions on Power Electronics, 31(2), 1576-1587. https://doi.org/10.1109/TPEL.2015.2418711

Knowledge of instantaneous junction temperature is essential for effective health management of power converters, enabling safe operation of the power semiconductors under all operating conditions. Methods based on fixed thermal models are typically... Read More about Application of Kalman Filter to Estimate Junction Temperature in IGBT Power Modules.

Quantitative Microstructure Characterization of Ag Nanoparticle Sintered Joints for Power Die Attachment (2014)
Journal Article
Wang, Y., Li, J., Agyakwa, P., Johnson, C. M., & Li, S. (2014). Quantitative Microstructure Characterization of Ag Nanoparticle Sintered Joints for Power Die Attachment. Molecular Crystals and Liquid Crystals, 604(1), 11-26. https://doi.org/10.1080/15421406.2014.967647

© 2014 Copyright © Taylor & Francis Group, LLC. The samples of sintered Ag joints for power die attachments were prepared using paste of Ag nanoparticles at 240°C and 5 MPa for 3 to 17 minutes. Their microstructural features were quantitatively cha... Read More about Quantitative Microstructure Characterization of Ag Nanoparticle Sintered Joints for Power Die Attachment.

Mission Profile-Based Reliability Design and Real-Time Life Consumption Estimation in Power Electronics (2014)
Journal Article
Mussallam, M., Yin, C., Bailey, C., & Johnson, C. M. (2015). Mission Profile-Based Reliability Design and Real-Time Life Consumption Estimation in Power Electronics. IEEE Transactions on Power Electronics, 30(5), 2601-2613. https://doi.org/10.1109/TPEL.2014.2358555

Power electronics are efficient for conversion and conditioning of the electrical energy through a wide range of applications. Proper life consumption estimation methods applied for power electronics that can operate in real time under in-service mis... Read More about Mission Profile-Based Reliability Design and Real-Time Life Consumption Estimation in Power Electronics.

Built-in reliability design of highly integrated solid-state power switches with metal bump interconnects (2014)
Journal Article
Li, J., Castellazzi, A., Dai, T., Corfield, M., Solomon, A. K., & Johnson, C. M. (2015). Built-in reliability design of highly integrated solid-state power switches with metal bump interconnects. IEEE Transactions on Power Electronics, 30(5), https://doi.org/10.1109/TPEL.2014.2357334

A stacked substrate–chip–bump–chip–substrate assembly has been demonstrated in the construction of power switch modules with high power density and good electrical performance. In this paper, special effort has been devoted to material selection and... Read More about Built-in reliability design of highly integrated solid-state power switches with metal bump interconnects.

Calibration of a novel microstructural damage model for wire bonds (2014)
Journal Article
Yang, L., Agyakwa, P., & Johnson, C. (2014). Calibration of a novel microstructural damage model for wire bonds. IEEE Transactions on Device and Materials Reliability, 14(4), 989-994. https://doi.org/10.1109/TDMR.2014.2354739

In a previous paper, a new time-domain damage-based physics model was proposed for the lifetime prediction of wire bond interconnects in power electronic modules. Unlike cycle-dependent life prediction methodologies, this model innovatively incorpora... Read More about Calibration of a novel microstructural damage model for wire bonds.

Reliability of thick Al wire: a study of the effects of wire bonding parameters on thermal cycling degradation rate using non-destructive methods (2014)
Journal Article
Arjmand, E., Agyakwa, P. A., & Johnson, C. M. (2014). Reliability of thick Al wire: a study of the effects of wire bonding parameters on thermal cycling degradation rate using non-destructive methods. Microelectronics Reliability, 54(9-10), https://doi.org/10.1016/j.microrel.2014.07.119

The effect of bonding parameters on the reliability of thick Al wire bond is investigated. Samples were prepared with 25 different designs with 5 different bonding parameters such as time, ultrasonic power, begin- force, end-force and touch-down step... Read More about Reliability of thick Al wire: a study of the effects of wire bonding parameters on thermal cycling degradation rate using non-destructive methods.

Bonding strength of multiple SiC die attachment prepared by sintering of Ag nanoparticles (2014)
Journal Article
Li, J., Johnson, C. M., Buttay, C., Sabbah, W., & Azzopardi, S. (2015). Bonding strength of multiple SiC die attachment prepared by sintering of Ag nanoparticles. Journal of Materials Processing Technology, 215, 299-308. https://doi.org/10.1016/j.jmatprotec.2014.08.002

3 mm × 3 mm dummy SiC dies with 100\200\200 nm thick Ti\W\Au metallization have simultaneously been attached using sintering of Ag nanoparticle paste on AlN-based direct bonded copper substrates with 5\0.1 μm thick NiP\Au finish. The effect of prepar... Read More about Bonding strength of multiple SiC die attachment prepared by sintering of Ag nanoparticles.

Integrated Half-Bridge Switch Using 70- ?m-Thin Devices and Hollow Interconnects (2014)
Journal Article
Solomon, A. K., Li, J., Castellazzi, A., & Johnson, C. M. (2015). Integrated Half-Bridge Switch Using 70- ?m-Thin Devices and Hollow Interconnects. IEEE Transactions on Industry Applications, 51(1), 556-566. https://doi.org/10.1109/TIA.2014.2334734

An application-oriented integration concept for a half-bridge switch assembly has been developed based on the latest generation 70- ?m-thin insulated gate bipolar transistors and diodes, which are rated at 600 V/200 A. This paper addresses the design... Read More about Integrated Half-Bridge Switch Using 70- ?m-Thin Devices and Hollow Interconnects.

Measurement of proton tunneling in short hydrogen bonds in single crystals of 3,5 pyridinedicarboxylic acid using nuclear magnetic resonance spectroscopy (2014)
Journal Article
Frantsuzov, I., Ford, S. J., Radosavljevic-Evans, I., Horsewill, A. J., Trommsdorff, H. P., & Johnson, M. R. (2014). Measurement of proton tunneling in short hydrogen bonds in single crystals of 3,5 pyridinedicarboxylic acid using nuclear magnetic resonance spectroscopy. Physical Review Letters, 113, https://doi.org/10.1103/PhysRevLett.113.018301

In this letter, we present NMR spin-lattice and relaxometry data for proton transfer in one of the shortest known N-H???O hydrogen bonds in a single crystal of 3,5 pyridinedicarboxylic acid (35PDCA). It is widely believed that proton transfer by quan... Read More about Measurement of proton tunneling in short hydrogen bonds in single crystals of 3,5 pyridinedicarboxylic acid using nuclear magnetic resonance spectroscopy.

Interdiffusion coefficients of binary multiphase systems with consideration of variation in Molar volumes (2014)
Journal Article
Li, J., Agyakwa, P., & Johnson, C. M. (2014). Interdiffusion coefficients of binary multiphase systems with consideration of variation in Molar volumes

This communication introduces a modification to the Wagner method to reveal and correct considerable systematic errors existing in the previously established analytical methods used to calculate the interdiffusion coefficients of binary multiphase sy... Read More about Interdiffusion coefficients of binary multiphase systems with consideration of variation in Molar volumes.

Suitable Thicknesses of Base Metal and Interlayer, and Evolution of Phases for Ag/Sn/Ag Transient liquid-phase Joints Used for Power Die Attachment (2014)
Journal Article
Li, J., Agyakwa, P., & Johnson, C. (2014). Suitable Thicknesses of Base Metal and Interlayer, and Evolution of Phases for Ag/Sn/Ag Transient liquid-phase Joints Used for Power Die Attachment. Journal of Electronic Materials, 43(4), 983-995. https://doi.org/10.1007/s11664-013-2971-7

Real Si insulated gate bipolar transistors with conventional Ni/Ag metallization and dummy Si chips with thickened Ni/Ag metallization have both been bonded, at 250°C for 0 min, 40 min, and 640 min, to Ag foil electroplated with 2.7 μm and 6.8 μm thi... Read More about Suitable Thicknesses of Base Metal and Interlayer, and Evolution of Phases for Ag/Sn/Ag Transient liquid-phase Joints Used for Power Die Attachment.

Symmetry-breaking in the endofullerene H2O@C60 revealed in the quantum dynamics of ortho and para-water: a neutron scattering investigation (2014)
Journal Article
Goh, K. S., Jimenez-Ruiz, M., Johnson, M. R., Rols, S., Ollivier, J., Denning, M. S., …Horsewill, A. J. (2014). Symmetry-breaking in the endofullerene H2O@C60 revealed in the quantum dynamics of ortho and para-water: a neutron scattering investigation. Physical Chemistry Chemical Physics, 16(39), https://doi.org/10.1039/c4cp03272a

Inelastic neutron scattering (INS) has been employed to investigate the quantum dynamics of water molecules permanently entrapped inside the cages of C60 fullerene molecules. This study of the supramolecular complex, H2O@C60, provides the unique oppo... Read More about Symmetry-breaking in the endofullerene H2O@C60 revealed in the quantum dynamics of ortho and para-water: a neutron scattering investigation.

Confirming a predicted selection rule in inelastic neutron scattering spectroscopy: the quantum translator-rotator H2 entrapped inside C60 (2014)
Journal Article
Xu, M., Jiménez-Ruiz, M., Johnson, M. R., Rols, S., Ye, S., Carravetta, M., …Horsewill, A. J. (2014). Confirming a predicted selection rule in inelastic neutron scattering spectroscopy: the quantum translator-rotator H2 entrapped inside C60. Physical Review Letters, 113(123001), https://doi.org/10.1103/PhysRevLett.113.123001

We report an inelastic neutron scattering (INS) study of H2 molecule encapsulated inside the fullerene C60 which confirms the recently predicted selection rule, the first to be established for the INS spectroscopy of aperiodic, discrete molecular com... Read More about Confirming a predicted selection rule in inelastic neutron scattering spectroscopy: the quantum translator-rotator H2 entrapped inside C60.

Design Optimization of Quasi-Active Gate Control for Series-Connected Power Devices (2013)
Journal Article
Teerakawanich, N., & Johnson, C. M. (2014). Design Optimization of Quasi-Active Gate Control for Series-Connected Power Devices. IEEE Transactions on Power Electronics, 29(6), 2705-2714. https://doi.org/10.1109/TPEL.2013.2274158

This paper presents a new gate drive circuit for driving a series string of insulated-gate bipolar transistors (IGBTs). The proposed quasi-active gate control (QAGC) circuit is simple to implement as it consists of only a few passive components in ad... Read More about Design Optimization of Quasi-Active Gate Control for Series-Connected Power Devices.