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Silicon Carbide n-IGBTs: Structure Optimization for Ruggedness Enhancement (2024)
Journal Article
Almpanis, I., Antoniou, M., Evans, P., Empringham, L., Gammon, P., Undrea, F., …Lophitis, N. (2024). Silicon Carbide n-IGBTs: Structure Optimization for Ruggedness Enhancement. IEEE Transactions on Industry Applications, https://doi.org/10.1109/tia.2024.3354870

In recent years, silicon carbide (SiC) based devices are increasingly replacing their silicon counterparts in power conversion applications due to their performance superiority. SiC insulated-gate bipolar transistors are particularly interesting as t... Read More about Silicon Carbide n-IGBTs: Structure Optimization for Ruggedness Enhancement.

10kV+ Rated SiC n-IGBTs: Novel Collector-Side Design Approach Breaking the Trade-Off between dV/dt and Device Efficiency (2023)
Journal Article
Almpanis, I., Evans, P., Antoniou, M., Gammon, P., Empringham, L., Undrea, F., …Lophitis, N. (2023). 10kV+ Rated SiC n-IGBTs: Novel Collector-Side Design Approach Breaking the Trade-Off between dV/dt and Device Efficiency. Key Engineering Materials, 946, 125-133. https://doi.org/10.4028/p-21h5lt

10kV+ rated 4H- Silicon Carbide (SiC) Insulated Gate Bipolar Transistors (IGBTs) have the potential to become the devices of choice in future Medium Voltage (MV) and High Voltage (HV) power converters. However, one significant performance concern of... Read More about 10kV+ Rated SiC n-IGBTs: Novel Collector-Side Design Approach Breaking the Trade-Off between dV/dt and Device Efficiency.

Compact Trench Floating Field Rings Termination for 10kV+ Rated SiC n-IGBTs (2022)
Journal Article
Lophitis, N., Gammon, P. M., Renz, A. B., Dai, T. X., Tiwari, A., Trajkovic, T., …Antoniou, M. (2022). Compact Trench Floating Field Rings Termination for 10kV+ Rated SiC n-IGBTs. Materials Science Forum, 1062, 598-602. https://doi.org/10.4028/p-64ey6u

This work presents the design methodology and performance of a compact edge termination structure aiming 10kV+ rated Silicon Carbide (SiC) devices. Standard Floating Field Rings (FFRs) for such high voltage rating SiC devices are not favored because... Read More about Compact Trench Floating Field Rings Termination for 10kV+ Rated SiC n-IGBTs.

Investigations of Short Circuit Robustness of SiC IGBTs with Considerations on Physics Properties and Design (2022)
Journal Article
Zhang, L. Y., Dai, T. X., Gammon, P. M., Lophitis, N., Udrea, F., Tiwari, A., …Antoniou, M. (2022). Investigations of Short Circuit Robustness of SiC IGBTs with Considerations on Physics Properties and Design. Materials Science Forum, 1062, 504-508. https://doi.org/10.4028/p-13z22g

The commercial success of silicon carbide (SiC) diodes and MOSFETs for the automotive industry has led many in the field to begin developing ultra-high voltage (UHV) SiC insulated gate bipolar transistors (IGBTs), rated from 6 kV to 30 kV, for future... Read More about Investigations of Short Circuit Robustness of SiC IGBTs with Considerations on Physics Properties and Design.

3C-SiC-on-Si MOSFETs: overcoming material technology limitations (2021)
Journal Article
Arvanitopoulos, A., Antoniou, M., Li, F., Jennings, M. R., Perkins, S., Gyftakis, K. N., & Lophitis, N. (2021). 3C-SiC-on-Si MOSFETs: overcoming material technology limitations. IEEE Transactions on Industry Applications, https://doi.org/10.1109/TIA.2021.3119269

The cubic polytype (3C-) of Silicon Carbide (SiC) is an emerging semiconductor technology for power devices. The featured isotropic material properties along with the Wide Band Gap (WBG) characteristics make it an excellent choice for power Metal Oxi... Read More about 3C-SiC-on-Si MOSFETs: overcoming material technology limitations.

Holistic Approach To Understanding Battery Degradation (2021)
Journal Article
Stocker, R., Mumtaz, A., & Lophitis, N. (2021). Holistic Approach To Understanding Battery Degradation. Engineering Integrity Journal, 51, 20-28

Li-ion cell degradation has a strong impact on electric vehicle performance both directly, through performance reduction, and indirectly through deviating behavior away from initial control system calibration. This necessitates a process for evaluati... Read More about Holistic Approach To Understanding Battery Degradation.

Experimental and physics based study of the Schottky Barrier Height inhomogeneity and associated traps affecting 3C-SiC-on-Si Schottky Barrier Diodes (2021)
Journal Article
Arvanitopoulos, A., Li, F., Jennings, M. R., Perkins, S., Gyftakis, K. N., Mawby, P., …Lophitis, N. (2021). Experimental and physics based study of the Schottky Barrier Height inhomogeneity and associated traps affecting 3C-SiC-on-Si Schottky Barrier Diodes. IEEE Transactions on Industry Applications, 57(5), 5252-5263. https://doi.org/10.1109/TIA.2021.3087667

The ability of cubic phase (3C-) Silicon Carbide (SiC) to grow heteroepitaxially on Silicon (Si) substrates (3C-SiC-on-Si) is an enabling feature for cost-effective Wide Bandgap devices and homogeneous integration with Si devices. In this paper, the... Read More about Experimental and physics based study of the Schottky Barrier Height inhomogeneity and associated traps affecting 3C-SiC-on-Si Schottky Barrier Diodes.

Universal Li-Ion Cell Electro-Thermal Model (2020)
Journal Article
Stocker, R., Mumtaz, A., Braglia, M., & Lophitis, N. (2020). Universal Li-Ion Cell Electro-Thermal Model. IEEE Transactions on Transportation Electrification, 7(1), 6-15. https://doi.org/10.1109/TTE.2020.2986606

This paper describes and verifies a Li-ion cell electro-thermal model and the associated data analysis process. It is designed to be adaptable and give accurate results across all variations of operating conditions and cell design based only on time... Read More about Universal Li-Ion Cell Electro-Thermal Model.

A Defects-Based Model on the Barrier Height Behavior in 3C-SiC-on-Si Schottky Barrier Diodes (2019)
Journal Article
Arvanitopoulos, A. E., Antoniou, M., Jennings, M. R., Perkins, S., Gyftakis, K. N., Mawby, P., & Lophitis, N. (2020). A Defects-Based Model on the Barrier Height Behavior in 3C-SiC-on-Si Schottky Barrier Diodes. IEEE Journal of Emerging and Selected Topics in Power Electronics, 8(1), 54-65. https://doi.org/10.1109/JESTPE.2019.2942714

3C-silicon carbide (3C-SiC) Schottky barrier diodes (SBDs) on silicon (Si) substrates (3C-SiC-on-Si) have been found to suffer from excessive subthreshold current, despite the superior electrical properties of 3C-SiC. In turn, that is one of the fact... Read More about A Defects-Based Model on the Barrier Height Behavior in 3C-SiC-on-Si Schottky Barrier Diodes.

On the broken rotor bar diagnosis using time-frequency analysis: 'Is one spectral representation enough for the characterisation of monitored signals?' (2019)
Journal Article
Panagiotou, P., Arvanitakis, I., Lophitis, N., Antonino-Daviu, {. A., & Gyftakis, {. N. (2019). On the broken rotor bar diagnosis using time-frequency analysis: 'Is one spectral representation enough for the characterisation of monitored signals?'. IET Electric Power Applications, 13(7), 932-942. https://doi.org/10.1049/iet-epa.2018.5512

© 2019 Institution of Engineering and Technology. All rights reserved. This work enhances the knowledge of the diagnostic potential of the broken bar fault in induction motors. Since a series of studies have been published over the years regarding co... Read More about On the broken rotor bar diagnosis using time-frequency analysis: 'Is one spectral representation enough for the characterisation of monitored signals?'.

FEM approach for diagnosis of induction machines' non-adjacent broken rotor bars by short-time Fourier transform spectrogram (2019)
Journal Article
Panagiotou, P., Arvanitakis, I., Lophitis, N., Antonino-Daviu, {. A., & Gyftakis, {. N. (2019). FEM approach for diagnosis of induction machines' non-adjacent broken rotor bars by short-time Fourier transform spectrogram. Journal of Engineering, 2019(17), 4566--4570. https://doi.org/10.1049/joe.2018.8240

Rotor electrical faults are an issue frequently encountered when applying condition monitoring and fault diagnosis on induction machines. The detection via the analysis of the stator current becomes challenging when the rotor cage suffers from multip... Read More about FEM approach for diagnosis of induction machines' non-adjacent broken rotor bars by short-time Fourier transform spectrogram.

Retrograde p-well for 10-kv class sic igbts (2019)
Journal Article
Tiwari, A. K., Antoniou, M., Lophitis, N., Perkin, S., Trajkovic, T., & Udrea, F. (2019). Retrograde p-well for 10-kv class sic igbts. IEEE Transactions on Electron Devices, 66(7), 3066-3072. https://doi.org/10.1109/TED.2019.2918008

In this paper, we propose the use of a retrograde doping profile for the p-well for ultrahigh voltage (>10 kV) SiC IGBTs. We show that the retrograde p-well effectively addresses the punchthrough issue, whereas offering a robust control over the gate... Read More about Retrograde p-well for 10-kv class sic igbts.

On the suitability of 3C-Silicon carbide as an alternative to 4H-silicon carbide for power diodes (2019)
Journal Article
Arvanitopoulos, A. E., Antoniou, M., Perkins, S., Jennings, M., Guadas, M. B., Gyftakis, K. N., & Lophitis, N. (2019). On the suitability of 3C-Silicon carbide as an alternative to 4H-silicon carbide for power diodes. IEEE Transactions on Industry Applications, 55(4), 4080-4090. https://doi.org/10.1109/TIA.2019.2911872

Major recent developments in growth expertise related to the cubic polytype of Silicon Carbide, the 3C-SiC, coupled with its remarkable physical properties and the low fabrication cost, suggest that within the next years, 3C-SiC devices can become a... Read More about On the suitability of 3C-Silicon carbide as an alternative to 4H-silicon carbide for power diodes.

A New Approach for Broken Rotor Bar Detection in Induction Motors Using Frequency Extraction in Stray Flux Signals (2019)
Journal Article
Panagiotou, P. A., Arvanitakis, I., Lophitis, N., Antonino-Daviu, J. A., & Gyftakis, K. N. (2019). A New Approach for Broken Rotor Bar Detection in Induction Motors Using Frequency Extraction in Stray Flux Signals. IEEE Transactions on Industry Applications, 55(4), 3501-3511. https://doi.org/10.1109/TIA.2019.2905803

This paper offers a reliable solution to the detection of broken rotor bars in induction machines with a novel methodology, which is based on the fact that the fault-related harmonics will have oscillating amplitudes due to the speed ripple effect. T... Read More about A New Approach for Broken Rotor Bar Detection in Induction Motors Using Frequency Extraction in Stray Flux Signals.

Deep p-Ring Trench Termination: An Innovative and Cost-Effective Way to Reduce Silicon Area (2019)
Journal Article
Antoniou, M., Lophitis, N., Udrea, F., Rahimo, M., Vemulapati, U., Corvasce, C., & Badstuebner, U. (2019). Deep p-Ring Trench Termination: An Innovative and Cost-Effective Way to Reduce Silicon Area. IEEE Electron Device Letters, 40(2), 177-180. https://doi.org/10.1109/LED.2018.2890702

© 1980-2012 IEEE. A new type of high-voltage termination, namely the 'deep p-ring trench' termination design for high-voltage, high-power devices, is presented and extensively simulated. Termination of such devices consumes a large proportion of the... Read More about Deep p-Ring Trench Termination: An Innovative and Cost-Effective Way to Reduce Silicon Area.

Optimal Gate Commutated Thyristor Design for Bi-Mode Gate Commutated Thyristors Underpinning High, Temperature Independent, Current Controllability (2018)
Journal Article
Lophitis, N., Antoniou, M., Vemulapati, U., Vobecky, J., Badstuebner, U., Wikstroem, T., …Udrea, F. (2018). Optimal Gate Commutated Thyristor Design for Bi-Mode Gate Commutated Thyristors Underpinning High, Temperature Independent, Current Controllability. IEEE Electron Device Letters, 39(9), 1342-1345. https://doi.org/10.1109/LED.2018.2847050

The bi-mode gate commutated thyristor (GCT) is an advanced reverse conducting device aiming high-power applications. Due to the high degree of interdigitation of diode parts and GCT parts, it is necessary to investigate how to best separate the two a... Read More about Optimal Gate Commutated Thyristor Design for Bi-Mode Gate Commutated Thyristors Underpinning High, Temperature Independent, Current Controllability.

Validated physical models and parameters of bulk 3C-SiC aiming for credible technology computer aided design (TCAD) simulation (2017)
Journal Article
Arvanitopoulos, A., Lophitis, N., Gyftakis, K. N., Perkins, S., & Antoniou, M. (2017). Validated physical models and parameters of bulk 3C-SiC aiming for credible technology computer aided design (TCAD) simulation. Semiconductor Science and Technology, 32(10), https://doi.org/10.1088/1361-6641/aa856b

© 2017 IOP Publishing Ltd. The cubic form of SiC (β- or 3C-) compared to the hexagonal α-SiC polytypes, primarily 4H- and 6H-SiC, has lower growth cost and can be grown heteroepitaxially in large area silicon (Si) wafers which makes it of special int... Read More about Validated physical models and parameters of bulk 3C-SiC aiming for credible technology computer aided design (TCAD) simulation.

On the Investigation of the “Anode Side” SuperJunction IGBT Design Concept (2017)
Journal Article
Antoniou, M., Lophitis, N., Udrea, F., Bauer, F., Vemulapati, U. R., & Badstuebner, U. (2017). On the Investigation of the “Anode Side” SuperJunction IGBT Design Concept. IEEE Electron Device Letters, 38(8), 1063-1066. https://doi.org/10.1109/led.2017.2718619

© 2017 IEEE. In this letter, we present the "anode-side" SuperJunction trench field stop+ IGBT concept with drift region SuperJunction pillars placed at the anode side of the structure rather than the cathode side. The extent of the pillars toward th... Read More about On the Investigation of the “Anode Side” SuperJunction IGBT Design Concept.

New Bi-Mode Gate-Commutated Thyristor Design Concept for High-Current Controllability and Low ON-State Voltage Drop (2016)
Journal Article
Lophitis, N., Antoniou, M., Vemulapati, U., Arnold, M., Nistor, I., Vobecky, J., …Udrea, F. (2016). New Bi-Mode Gate-Commutated Thyristor Design Concept for High-Current Controllability and Low ON-State Voltage Drop. IEEE Electron Device Letters, 37(4), 467-470. https://doi.org/10.1109/led.2016.2533572

© 2016 IEEE. A new design approach for bi-mode gatecommutated thyristors (BGCTs) is proposed for high-current controllability and low ON-state voltage drop. Using a complex multi-cell mixed-mode simulation model which can capture the maximum controll... Read More about New Bi-Mode Gate-Commutated Thyristor Design Concept for High-Current Controllability and Low ON-State Voltage Drop.

Improving Current Controllability in Bi-Mode Gate Commutated Thyristors (2015)
Journal Article
Lophitis, N., Antoniou, M., Udrea, F., Vemulapati, U., Arnold, M., Nistor, I., …Rahimo, M. (2015). Improving Current Controllability in Bi-Mode Gate Commutated Thyristors. IEEE Transactions on Electron Devices, 62(7), 2263-2269. https://doi.org/10.1109/TED.2015.2428994

© 2015 IEEE. The Bi-mode gate commutated thyristor (BGCT) is a new type of reverse conducting Gate Commutated Thyristor (GCT). This paper focuses on the maximum controllable current capability of BGCTs and proposes new solutions which can increase it... Read More about Improving Current Controllability in Bi-Mode Gate Commutated Thyristors.

Novel Approach Toward Plasma Enhancement in Trench-Insulated Gate Bipolar Transistors (2015)
Journal Article
Antoniou, M., Lophitis, N., Bauer, F., Nistor, I., Bellini, M., Rahimo, M., …Udrea, F. (2015). Novel Approach Toward Plasma Enhancement in Trench-Insulated Gate Bipolar Transistors. IEEE Electron Device Letters, 36(8), 823-825. https://doi.org/10.1109/LED.2015.2433894

In this letter, a trench-insulated gate bipolar transistor (IGBT) design with local charge compensating layers featured at the cathode of the device is presented and analyzed. The superjunction or reduced surface effect proves to be very effective in... Read More about Novel Approach Toward Plasma Enhancement in Trench-Insulated Gate Bipolar Transistors.

Parameters influencing the maximum controllable current in gate commutated thyristors (2014)
Journal Article
Lophitis, N., Antoniou, M., Udrea, F., Nistor, I., Arnold, M., Wikstro?m, T., & Vobecky, J. (2014). Parameters influencing the maximum controllable current in gate commutated thyristors. IET Circuits, Devices and Systems, 8(3), 221--226. https://doi.org/10.1049/iet-cds.2013.0217

The model of interconnected numerical device segments can give a prediction on the dynamic performance of large area full wafer devices such as the Gate Commutated Thyristors (GCTs) and can be used as an optimisation tool for designing GCTs. In this... Read More about Parameters influencing the maximum controllable current in gate commutated thyristors.

Gate commutated thyristor with voltage independent maximum controllable current (2013)
Journal Article
Lophitis, N., Antoniou, M., Udrea, F., Nistor, I., Rahimo, {. T., Arnold, M., …Vobecky, J. (2013). Gate commutated thyristor with voltage independent maximum controllable current. IEEE Electron Device Letters, 34(8), 954--956. https://doi.org/10.1109/LED.2013.2267552

In this letter, we use a novel 3-D model, earlier calibrated with experimental results on standard gate commutated thyristors (GCTs), with the aim to explain the physics behind the high-power technology (HPT) GCT, to investigate what impact this desi... Read More about Gate commutated thyristor with voltage independent maximum controllable current.

The destruction mechanism in GCTs (2013)
Journal Article
Lophitis, N., Antoniou, M., Udrea, F., Bauer, F. D., Nistor, I., Arnold, M., …Vobecky, J. (2013). The destruction mechanism in GCTs. IEEE Transactions on Electron Devices, 60(2), 819-826. https://doi.org/10.1109/TED.2012.2235442

This paper focuses on the causes that lead to the final destruction in standard gate-commutated thyristor (GCT) devices. A new 3-D model approach has been used for simulating the GCT which provides a deep insight into the operation of the GCT in extr... Read More about The destruction mechanism in GCTs.