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Author

Daniel J. Lichtenwalner

Other affiliations: Cree Inc., Durham University
Bio: Daniel J. Lichtenwalner is an academic researcher from Research Triangle Park. The author has contributed to research in topics: Power semiconductor device & Gate oxide. The author has an hindex of 12, co-authored 37 publications receiving 585 citations. Previous affiliations of Daniel J. Lichtenwalner include Cree Inc. & Durham University.

Papers
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Proceedings ArticleDOI
15 Jun 2014
TL;DR: In this article, the 4H-SiC MOSFETs were further optimized for high power, high-frequency, and high-voltage energy conversion and transmission applications and achieved new breakthrough performance for voltage ratings from 900 V up to 15 kV.
Abstract: Since Cree, Inc.'s 2 nd generation 4H-SiC MOSFETs were commercially released with a specific on-resistance (R ON, SP ) of 5 mΩ·cm 2 for a 1200 V-rating in early 2013, we have further optimized the device design and fabrication processes as well as greatly expanded the voltage ratings from 900 V up to 15 kV for a much wider range of high-power, high-frequency, and high-voltage energy-conversion and transmission applications. Using these next-generation SiC MOSFETs, we have now achieved new breakthrough performance for voltage ratings from 900 V up to 15 kV with a R ON, SP as low as 2.3 mΩ·cm 2 for a breakdown voltage (BV) of 1230 V and 900 V-rating, 2.7 mΩ·cm 2 for a BV of 1620 V and 1200 V-rating, 3.38 mΩ·cm 2 for a BV of 1830 V and 1700 V-rating, 10.6 mΩ·cm 2 for a BV of 4160 V and 3300 V-rating, 123 mΩ·cm 2 for a BV of 12 kV and 10 kV-rating, and 208 mΩ·cm 2 for a BV of 15.5 kV and 15 kV-rating. In addition, due to the lack of current tailing during the bipolar device switching turn-off, the SiC MOSFETs reported in this work exhibit incredibly high frequency switching performance over their silicon counter parts.

236 citations

Journal ArticleDOI
TL;DR: In this article, the authors investigated the interface passivation materials for metal-oxide-semiconductor field effect transistors (MOSFETs) on 4H-SiC (0001).
Abstract: Alkali (Rb and Cs) and alkaline earth (Ca, Sr, and Ba) elements have been investigated as interface passivation materials for metal-oxide-semiconductor field-effect transistors (MOSFETs) on 4H-SiC (0001). While the alkali elements Rb and Cs result in field-effect mobility (μFE) values > 25 cm2/V·s, the alkaline earth elements Sr and Ba resulted in higher μFE values of 40 and 85 cm2/V·s, respectively. The Ba-modified MOSFETs show a slight decrease in mobility with heating to 150 °C, as expected when mobility is not interface-trap-limited, but phonon-scattering-limited. With a Ba interface layer, the interface state density 0.25 eV below the conduction band is ∼3 × 1011 cm−2 eV−1, lower than that obtained with nitric oxide passivation. Devices show stable threshold voltage under 2 MV/cm gate bias stress at 175 °C, indicating no mobile ions. Secondary-ion mass spectrometry shows that the Sr and Ba stay predominantly at the interface after oxidation anneals.

66 citations

Journal ArticleDOI
TL;DR: In this article, the authors show that the boundary between leakage current degradation and a single event-burnout-like effect is a strong function of linear energy transfer and reverse bias, consistent with the hypothesis that ion energy causes eutectic-like intermixture at the metal-semiconductor interface or localized melting of the silicon carbide lattice.
Abstract: Ion-induced degradation and catastrophic failures in high-voltage SiC junction barrier Schottky power diodes are investigated. The experimental results agree with earlier data showing discrete jumps in leakage current for individual ions and show that the boundary between leakage current degradation and a single-event-burnout-like effect is a strong function of linear energy transfer and reverse bias. TCAD simulations show high localized electric fields under the Schottky junction, and high temperatures generated directly under the Schottky contact, consistent with the hypothesis that the ion energy causes eutectic-like intermixture at the metal–semiconductor interface or localized melting of the silicon carbide lattice.

59 citations

Proceedings ArticleDOI
11 Mar 2018
TL;DR: Results demonstrate the reliability of SiC MOSFETs under high-field operation and the device failure rate due to terrestrial neutron single-event burnout (SEB) is shown to be comparable or superior to that of Si devices.
Abstract: Power metal-oxide-semiconductor field-effect transistors (MOSFETs) experience conditions of high field during normal operation, with high MOS gate oxide field in the on-state, and high drift and termination fields in the blocking state. Moreover, silicon carbide devices typically experience higher fields than comparable Si devices due to channel and drift property differences. SiC MOSFET threshold voltage stability and gate oxide lifetime under high gate oxide field are observed to follow the same functional form as Si devices. SiC MOSFETs demonstrate intrinsic oxide lifetime greater than 107 hrs in time-dependent dielectric breakdown (TDDB) testing. Accelerated high-temperature reverse-bias (HTRB) testing above the rated voltage reveals similarly long lifetime under high drift fields. The device failure rate due to terrestrial neutron single-event burnout (SEB) is shown to be comparable or superior to that of Si devices. Results demonstrate the reliability of SiC MOSFETs under high-field operation.

46 citations

Proceedings ArticleDOI
01 Jan 2016
TL;DR: In this article, the wear-out mechanisms and intrinsic reliability performance of power SiC devices as characterized by time-dependent dielectric breakdown (TDDB), accelerated life test high temperature reverse bias (ALT-HTRB), terrestrial neutron exposure, and power cycling are discussed.
Abstract: SiC power devices offer performance advantages over competing Si-based power devices, due to the wide bandgap and other key materials properties of 4H-SiC. For example, SiC can more easily be used to fabricate MOSFETs with very high voltage ratings (up to 10 kV), and with lower switching losses. The reliability of SiC power devices is excellent and has continued to improve due to continuing advancements in SiC substrate quality, epitaxial growth capabilities, and device processing. This has enabled the continually accelerating growth of SiC power device commercial adoption. This paper reviews the wear-out mechanisms and intrinsic reliability performance of power SiC devices as characterized by time-dependent dielectric breakdown (TDDB), accelerated life test high temperature reverse bias (ALT-HTRB), terrestrial neutron exposure, and power cycling. This paper also reviews some of the known failure mechanisms that have been characterized and addressed through technological advances. Finally, we present field return data that demonstrates less than 5 FIT (fails per billion device hours) for commercially produced SiC MOSFETs and Schottky diodes, with over 2 trillion device field hours.

41 citations


Cited by
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Journal ArticleDOI
TL;DR: In this article, the authors review some emerging trends in the processing of wide band gap (WBG) semiconductor devices (e.g., diodes, MOSFETs, HEMTs, etc.).

242 citations

Journal ArticleDOI
TL;DR: In this paper, the authors reviewed the most exciting recent progress in interface engineering for improving the channel mobility and fundamental understanding of channel transport in 4H-SiC power metal oxide Semiconductor Field Effect Transistors.
Abstract: A sustainable energy future requires power electronics that can enable significantly higher efficiencies in the generation, distribution, and usage of electrical energy. Silicon carbide (4H-SiC) is one of the most technologically advanced wide bandgap semiconductor that can outperform conventional silicon in terms of power handling, maximum operating temperature, and power conversion efficiency in power modules. While SiC Schottky diode is a mature technology, SiC power Metal Oxide Semiconductor Field Effect Transistors are relatively novel and there is large room for performance improvement. Specifically, major initiatives are under way to improve the inversion channel mobility and gate oxide stability in order to further reduce the on-resistance and enhance the gate reliability. Both problems relate to the defects near the SiO2/SiC interface, which have been the focus of intensive studies for more than a decade. Here we review research on the SiC MOS physics and technology, including its brief history, the state-of-art, and the latest progress in this field. We focus on the two main scientific problems, namely, low channel mobility and bias temperature instability. The possible mechanisms behind these issues are discussed at the device physics level as well as the atomic scale, with the support of published physical analysis and theoretical studies results. Some of the most exciting recent progress in interface engineering for improving the channel mobility and fundamental understanding of channel transport is reviewed.

220 citations

Journal ArticleDOI
TL;DR: In this paper, a state-of-the-art 325 A, 1700 V SiC mosfet module has been fully characterized under various load currents, bus voltages, and gate resistors to reveal their switching capability.
Abstract: The higher voltage blocking capability and faster switching speed of silicon-carbide (SiC) mosfet s have the potential to replace Si insulated gate bipolar transistors (IGBTs) in medium-/low-voltage and high-power applications. In this paper, a state-of-the-art commercially available 325 A, 1700 V SiC mosfet module has been fully characterized under various load currents, bus voltages, and gate resistors to reveal their switching capability. Meanwhile, Si IGBT modules with similar power ratings are also tested under the same conditions. From the test results, several interesting points have been obtained: different to the Si IGBT module, the over-shoot current of the SiC mosfet module increases linearly with the increase of the load current and it has been explained by a model of the over-shoot current proposed in this paper; the induced negative gate voltage due to the complementary device turn- off (crosstalk effect) is more harmful to the SiC mosfet module than the induced positive gate voltage during turn- on when the gate off-voltage is –6 V; the maximum dv / dt and di / dt (electromagnetic interference) during switching transients of the SiC mosfet module are close to those of the Si IGBT module when the gate resistance is larger than 8 Ω but the switching loss of the SiC mosfet module is much smaller; the switching losses of the Si IGBT module are greater than those of the SiC mosfet module even when the gate resistance of the former is reduced to zero. An accurate power loss model, which is suitable for a three-phase two-level converter based on SiC mosfet modules considering the power loss of the parasitic capacitance, has been presented and verified in this paper. From the model, a 96.2% efficiency can be achieved at the switching frequency of 80 kHz and the power of 100 kW.

218 citations

Journal ArticleDOI
14 Jan 2019
TL;DR: The problems of high common mode currents and bearing and insulation damage, which are caused by high dv/dt, and the reliability of WBG devices are discussed.
Abstract: Wide bandgap (WBG) device-based power electronics converters are more efficient and lightweight than silicon-based converters. WBG devices are an enabling technology for many motor drive applications and new classes of compact and efficient motors. This paper reviews the potential applications and advances enabled by WBG devices in ac motor drives. Industrial motor drive products using WBG devices are reviewed, and the benefits are highlighted. This paper also discusses the technical challenges, converter design considerations, and design tradeoffs in realizing the full potential of WBG devices in motor drives. There is a tradeoff between high switching frequency and other issues such as high dv/dt and electromagnetic interference. The problems of high common mode currents and bearing and insulation damage, which are caused by high dv/dt , and the reliability of WBG devices are discussed.

207 citations

Patent
27 Jan 2012
TL;DR: In this paper, a silicon-carbide semiconductor device (101) has a main electrode (52), a first barrier layer (70a), and a wiring layer (60), which is made from a conductive material that does not contain aluminum.
Abstract: This silicon-carbide semiconductor device (101) has a silicon-carbide substrate (10), a main electrode (52), a first barrier layer (70a), and a wiring layer (60). The main electrode (52) is provided directly on top of the silicon-carbide substrate (10). The first barrier layer (70a) is provided on top of the main electrode (52) and is made from a conductive material that does not contain aluminum. The wiring layer (60) is provided on top of the first barrier layer (70a), is isolated from the main electrode (52) by the first barrier layer (70a), and is made from a material that does contain aluminum.

180 citations