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Author

Lukas Kranz

Bio: Lukas Kranz is an academic researcher. The author has contributed to research in topics: MOSFET & Short circuit. The author has an hindex of 6, co-authored 23 publications receiving 91 citations.

Papers
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Proceedings ArticleDOI
01 May 2017
TL;DR: LinPak half-bridge modules have been fabricated showing reduction of the switching loss by more than 90% compared to a silicon IGBT/diode half bridge as discussed by the authors, and they are able to withstand short circuit pulse of up to 10μs and a 9ms surge current event up to 15 times the nominal current.
Abstract: An approach to implement electrically robust MOSFETs in a functioning half-bridge will be investigated. For the first time, reverse conducting 3.3kV SiC MOSFETs have been fabricated with dilferent cell pitches from 14μm (p1.0) to 26μm (pl.8) that are able to withstand short circuit pulse of up to 10μs and a 9ms surge current event up to 15x the nominal current. LinPak half-bridge modules have been fabricated showing reduction of the switching loss by more than 90% compared to a silicon IGBT/diode half bridge.

27 citations

Journal ArticleDOI
TL;DR: In this article, the electrical activation of 1×1020 cm-3 implanted Al in 4H-SiC has been studied in the temperature range 1500 - 1950 °C by the analysis of the sheet resistance of the Al implanted layers, as measured at room temperature.
Abstract: The electrical activation of 1×1020 cm-3 implanted Al in 4H-SiC has been studied in the temperature range 1500 - 1950 °C by the analysis of the sheet resistance of the Al implanted layers, as measured at room temperature. The minimum annealing time for reaching stationary electrical at fixed annealing temperature has been found. The samples with stationary electrical activation have been used to estimate the thermal activation energy for the electrical activation of the implanted Al.

19 citations

Proceedings ArticleDOI
19 May 2019
TL;DR: In this paper, the authors demonstrate the integration of high-k/metal gate stacks in vertical 1.2kV SiC power MOSFETs including static and dynamic characterization as well as safe operation area (SOA).
Abstract: We demonstrate the first integration of high-k/metal gate stacks in vertical 1.2kV SiC power MOSFETs including static and dynamic characterization as well as safe operation area (SOA). The high-k/4H-SiC MOS interface exhibits a remarkably low interface defect state density and improved threshold voltage stability compared to conventional gate stacks based on SiO 2 . Moreover, we achieved an impressive performance boost in terms of on-resistance due to this low-defective interface and increased gate capacitance. Compared to vertical devices with SiO 2 /poly Si gate stacks these devices exhibit a negligible hysteresis.

15 citations

Proceedings ArticleDOI
01 Dec 2018
TL;DR: In this paper, the static and dynamic performance of 3.3 and 6.5kV-rated SiC MOSFETs was evaluated and benchmarked against similarly rated state-of-the-art Si IGBTs.
Abstract: This paper reviews the recent progress of SiC MOSFETs rated above 3.3kV. The static and dynamic performance of 3.3 and 6.5kV-rated MOSFETs will be evaluated and benchmarked against similarly rated state-of-the-art Si IGBTs. A numerical comparison between high voltage (15kV) SiC MOSFETs and IGBTs will also be provided. The paper will also attempt to comment on the future challenges facing high voltage (HV) devices in SiC technology.

14 citations

Proceedings ArticleDOI
19 May 2019
TL;DR: The static and dynamic performance of Silicon Carbide (SiC) MOSFET rated for 1200V applications has been investigated in this paper, where a novel retrograde doping profile has been employed.
Abstract: The static and dynamic performance of Silicon Carbide (SiC) MOSFET rated for 1200V applications has been investigated. MOSFETs with a planar design and several different cell pitches have been fabricated. Special attention has been dedicated to the channel design, where a novel retrograde doping profile has been employed. For reference, a more common box profile channel has also been used. Turn-off measurements under high current and over voltage conditions reveal that the MOSFET body diode offers wide safe operating area capability. The MOSFETs feature exceptional ruggedness against long short circuit events, with the retrograde channel designs able to withstand the $10\boldsymbol{\mu} \mathbf{s}$ industry standard specification.

10 citations


Cited by
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Journal Article
TL;DR: This work presents a list of physical criteria that deep center defects and their hosts should meet and explains how these requirements can be used in conjunction with electronic structure theory to intelligently sort through candidate defect systems.
Abstract: Identifying and designing physical systems for use as qubits, the basic units of quantum information, are critical steps in the development of a quantum computer. Among the possibilities in the solid state, a defect in diamond known as the nitrogen-vacancy (NV-1) center stands out for its robustness—its quantum state can be initialized, manipulated, and measured with high fidelity at room temperature. Here we describe how to systematically identify other deep center defects with similar quantum-mechanical properties. We present a list of physical criteria that these centers and their hosts should meet and explain how these requirements can be used in conjunction with electronic structure theory to intelligently sort through candidate defect systems. To illustrate these points in detail, we compare electronic structure calculations of the NV-1 center in diamond with those of several deep centers in 4H silicon carbide (SiC). We then discuss the proposed criteria for similar defects in other tetrahedrally coordinated semiconductors.

421 citations

Journal ArticleDOI
TL;DR: It is concluded that, although SiC and GaN are currently the only WBG materials available on the semiconductor portfolio, they may be displaced by others such as Ga2O3 in the near future.
Abstract: At present, the energy transition is leading to the replacement of large thermal power plants by distributed renewable generation and the introduction of different assets. Consequently, a massive deployment of power electronics is expected. A particular case will be the devices destined for urban environments and smart grids. Indeed, such applications have some features that make wide bandgap (WBG) materials particularly relevant. This paper analyzes the most important features expected by future smart applications from which the characteristics that their power semiconductors must perform can be deduced. Following, not only the characteristics and theoretical limits of wide bandgap materials already available on the market (SiC and GaN) have been analyzed, but also those currently being researched as promising future alternatives (Ga2O3, AlN, etc.). Finally, wide bandgap materials are compared under the needs determined by the smart applications, determining the best suited to them. We conclude that, although SiC and GaN are currently the only WBG materials available on the semiconductor portfolio, they may be displaced by others such as Ga2O3 in the near future.

45 citations

Journal ArticleDOI
TL;DR: This work investigated the electrical and spectroscopic performance of an innovative position-sensitive semiconductor radiation detector in epitaxial 4H-SiC, and found that the prototype detector is suitable for high resolution X-ray spectroscopy with imaging capability in a wide range of operating temperatures.
Abstract: Compared with the most commonly used silicon and germanium, which need to work at cryogenic or low temperatures to decrease their noise levels, wide-bandgap compound semiconductors such as silicon carbide allow the operation of radiation detectors at room temperature, with high performance, and without the use of any bulky and expensive cooling equipment. In this work, we investigated the electrical and spectroscopic performance of an innovative position-sensitive semiconductor radiation detector in epitaxial 4H-SiC. The full depletion of the epitaxial layer (124 µm, 5.2 × 1013 cm−3) was reached by biasing the detector up to 600 V. For comparison, two different microstrip detectors were fully characterized from −20 °C to +107 °C. The obtained results show that our prototype detector is suitable for high resolution X-ray spectroscopy with imaging capability in a wide range of operating temperatures.

44 citations

Proceedings ArticleDOI
Boxue Hu1, Xintong Lyu1, Diang Xing1, Dihao Ma1, Risha Na1, Jin Wang1 
01 Sep 2018
TL;DR: A summary of recent advances in medium voltage (MV) SiC power devices, including MOSFETs, IGBTs, GTOs and super-cascode devices, is presented in this article.
Abstract: Medium voltage (MV) Silicon Carbide (SiC) power devices have become available as engineering samples. Recent studies show that they outperform their Silicon (Si) counterparts regarding voltage blocking capability, specific on-state resistance, switching speed and maximum allowable junction temperature. It is projected that MV SiC power devices will bring revolutionary changes in medium and high voltage applications such as traction drives for locomotives, industrial motor drives, utility power transmission systems, etc. This paper presents a summary of recent advances in MV SiC power devices, including MOSFETs, IGBTs, GTOs and super-cascode devices. Technical challenges of their applications such as device packaging, gate drive design and gate drive auxiliary power supply design are discussed. Testing results of three state-of-the-art MV SiC devices, including a 4 kV, 5 A discrete SiC MOSFET, a 4.5 kV, 40 A SiC super-cascode device and a 10 kV, 40 A SiC MOSFET power module, are presented as examples.

28 citations

Proceedings ArticleDOI
Shaowen Han1, Shu Yang1, Yongkai Li1, Yinxiang Liu1, Kuang Sheng1 
19 May 2019
TL;DR: In this article, the authors investigated the temperature-dependent forward conduction performance, the reverse recovery behavior and surge current capability of the vertical GaN Schottky barrier diode and PN diode.
Abstract: In this work, we investigate the temperature-dependent forward conduction performance, the reverse recovery behavior and surge current capability of the vertical GaN Schottky barrier diode (SBD) and PN diode (PND). Compared with the SBD, the vertical GaN PND can deliver photon-enhanced conductivity modulation (PECM), temperature-independent differential ON-resistance, and higher surge current capability. It is experimentally verified that the PECM and zero reverse recovery can be simultaneously realized in the vertical GaN PND.

27 citations