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Journal ArticleDOI

A Survey of Wide Bandgap Power Semiconductor Devices

01 May 2014-IEEE Transactions on Power Electronics (IEEE)-Vol. 29, Iss: 5, pp 2155-2163
TL;DR: In this article, a review of recent progresses in the development of SiC- and GaN-based power semiconductor devices together with an overall view of the state of the art of this new device generation is presented.
Abstract: Wide bandgap semiconductors show superior material properties enabling potential power device operation at higher temperatures, voltages, and switching speeds than current Si technology. As a result, a new generation of power devices is being developed for power converter applications in which traditional Si power devices show limited operation. The use of these new power semiconductor devices will allow both an important improvement in the performance of existing power converters and the development of new power converters, accounting for an increase in the efficiency of the electric energy transformations and a more rational use of the electric energy. At present, SiC and GaN are the more promising semiconductor materials for these new power devices as a consequence of their outstanding properties, commercial availability of starting material, and maturity of their technological processes. This paper presents a review of recent progresses in the development of SiC- and GaN-based power semiconductor devices together with an overall view of the state of the art of this new device generation.
Citations
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Journal ArticleDOI
TL;DR: The technology progress of SiC power devices and their emerging applications are reviewed and the design challenges and future trends are summarized.
Abstract: Silicon carbide (SiC) power devices have been investigated extensively in the past two decades, and there are many devices commercially available now. Owing to the intrinsic material advantages of SiC over silicon (Si), SiC power devices can operate at higher voltage, higher switching frequency, and higher temperature. This paper reviews the technology progress of SiC power devices and their emerging applications. The design challenges and future trends are summarized at the end of the paper.

806 citations


Cites background from "A Survey of Wide Bandgap Power Semi..."

  • ...Material properties comparison between Si and SiC (ranges 1−5 are marked for all five properties) [3]....

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  • ...5 kV, and the practical operating temperature is lower than 175 °C [3]....

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Journal ArticleDOI
TL;DR: In this article, the characteristics and commercial status of both vertical and lateral GaN power devices are reviewed, providing the background necessary to understand the significance of these recent developments and the challenges encountered in GaN-based converter design, such as the consequences of faster switching on gate driver and board layout.
Abstract: Gallium nitride (GaN) power devices are an emerging technology that have only recently become available commercially. This new technology enables the design of converters at higher frequencies and efficiencies than those achievable with conventional Si devices. This paper reviews the characteristics and commercial status of both vertical and lateral GaN power devices, providing the background necessary to understand the significance of these recent developments. In addition, the challenges encountered in GaN-based converter design are considered, such as the consequences of faster switching on gate driver design and board layout. Other issues include the unique reverse conduction behavior, dynamic $R_{\mathrm {{ds}},\mathrm {{on}}}$ , breakdown mechanisms, thermal design, device availability, and reliability qualification. This review will help prepare the reader to effectively design GaN-based converters, as these devices become increasingly available on a commercial scale.

769 citations

Book ChapterDOI
TL;DR: Luminescent ratiometric thermometers combining high spatial and temporal resolution at the micro-and nanoscale, where the conventional methods are ineffective, have emerged over the last decade as an effervescent field of research, essentially motivated by their potential applications in nanotechnology, photonics, and biomedicine as discussed by the authors.
Abstract: Luminescent ratiometric thermometers combining high spatial and temporal resolution at the micro- and nanoscale, where the conventional methods are ineffective, have emerged over the last decade as an effervescent field of research, essentially motivated by their potential applications in nanotechnology, photonics, and biomedicine. Among the distinct luminescent thermal probes, lanthanide-based materials play a central role in the field due to their unique thermometric response and intriguing emission features (eg, high quantum yield, narrow bandwidth, long-lived emission, large Stokes shifts, and ligand-dependent luminescence sensitization). This chapter offers a general overview of recent examples of single- and dual-center Ln3 +-based thermometers, emphasizing those working at nanometric scale, being focused on how to quantify their performance accordingly to the relevant parameters: relative sensitivity, temperature uncertainty, spatial and temporal resolution, repeatability (or test–retest reliability), and reproducibility. The emission mechanisms supporting single- and dual-center emissions are reviewed, together with the advantages and limitations of each approach. Illustrative examples of the rich variety of systems designed and developed to sense temperature are provided and explored. Finally, we discuss the challenges and opportunities in the development of highly sensitive luminescent ratiometric thermometers that are currently facing the scientists in this exciting research field.

330 citations

Journal ArticleDOI
TL;DR: This paper presents the design and implementation of a wireless power transfer (WPT) battery charger for an electric city car and describes in detail the design procedure of the power circuitry needed for its operation.
Abstract: Wireless power transfer systems (WPTSs) with inductive coupling are advantageously used to charge the battery pack of electric vehicles. They basically consist of coil coupling, power supply circuitry connected to the transmitting side of the coil coupling, and power-conditioning circuitry connected to the receiving side of the coil coupling. This paper presents the design and implementation of a wireless power transfer (WPT) battery charger for an electric city car. A short overview on the working principles of a series–series resonant WPTS is given before describing in detail the design procedure of the power circuitry needed for its operation, i.e., an alternating-current–direct-current converter cascaded by a high-frequency inverter in the transmitting section and a diode rectifier cascaded by a chopper in the receiving section. The coil coupling with spiral coils is designed with the help of a finite-element-method code. A prototype of the WPT battery charger is built up according to the design results, and experiments that validate the design procedure are carried out.

267 citations


Cites background from "A Survey of Wide Bandgap Power Semi..."

  • ...Due to the wide band gap of the SiC material and the consequent high breakdown voltage, these power devices benefit from a thinner voltage blocking layer that, together with the higher drift velocity of the free charges, reduces the parasitic capacitance of the power devices and gives them the ability of switching at very high frequencies with low commutation losses; moreover, they have a lower ON-resistance and, consequently, lower conduction losses [11]....

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Journal ArticleDOI
TL;DR: In this paper, the authors report switching performance of a new 1700-V, 50-A SiC MOSFET designed and developed by Cree, Inc. and compare it with other SiC devices.
Abstract: Due to wider band gap of silicon carbide (SiC) compared to silicon (Si), MOSFET made in SiC has considerably lower drift region resistance, which is a significant resistive component in high-voltage power devices. With low on-state resistance and its inherently low switching loss, SiC MOSFETs can offer much improved efficiency and compact size for the converter compared to those using Si devices. In this paper, we report switching performance of a new 1700-V, 50-A SiC MOSFET designed and developed by Cree, Inc. Hard-switching losses of the SiC MOSFETs with different circuit parameters and operating conditions are measured and compared with the 1700-V Si BiMOSFET and 1700-V Si IGBT, using same test set-up. Based on switching and conduction losses, the operating boundary of output power and switching frequency of these devices are found out in a dc–dc boost converter and compared. The switching $dv/dts$ and $di/dts$ of SiC MOSFET are captured and discussed in the perspective of converter design. To validate the continuous operation, three dc–dc boost converters using these devices, are designed and tested at 10 kW of power with 1 kV of output voltage and 10 kHz of switching frequency. 1700-V SiC Schottky diode is used as the blocking diode in each case. Corresponding converter efficiencies are evaluated and the junction temperature of each device is estimated. To demonstrate high switching frequency operation, the SiC MOSFET is switched upto 150 kHz within permissible junction temperature rise. A switch combination of the 1700-V SiC MOSFET and 1700-V SiC Schottky diode connected in series is also evaluated for zero voltage switching turn-ON behavior and compared with those of bipolar Si devices. Results show substantial power loss saving with the use of SiC MOSFET.

242 citations

References
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Journal ArticleDOI
Wataru Saito1, Yoshiharu Takada1, Masahiko Kuraguchi1, Kunio Tsuda1, Ichiro Omura1 
TL;DR: In this article, a recessed-gate structure was proposed to realize normally off operation of high-voltage AlGaN/GaN high-electron mobility transistors (HEMTs) for power electronics applications.
Abstract: A recessed-gate structure has been studied with a view to realizing normally off operation of high-voltage AlGaN/GaN high-electron mobility transistors (HEMTs) for power electronics applications. The recessed-gate structure is very attractive for realizing normally off high-voltage AlGaN/GaN HEMTs because the gate threshold voltage can be controlled by the etching depth of the recess without significant increase in on-resistance characteristics. With this structure the threshold voltage can be increased with the reduction of two-dimensional electron gas (2DEG) density only under the gate electrode without reduction of 2DEG density in the other channel regions such as the channel between drain and gate. The threshold-voltage increase was experimentally demonstrated. The threshold voltage of fabricated recessed-gate device increased to -0.14 V while the threshold voltage without the recessed-gate structure was about -4 V. The specific on-resistance of the device was maintained as low as 4 m/spl Omega//spl middot/cm/sup 2/ and the breakdown voltage was 435 V. The on-resistance and the breakdown voltage tradeoff characteristics were the same as those of normally on devices. From the viewpoint of device design, the on-resistance for the normally off device was modeled using the relationship between the AlGaN layer thickness under the gate electrode and the 2DEG density. It is found that the MIS gate structure and the recess etching without the offset region between recess edge and gate electrode will further improve the on-resistance. The simulation results show the possibility of the on-resistance below 1 m/spl Omega//spl middot/cm/sup 2/ for normally off AlGaN/GaN HEMTs operating at several hundred volts with threshold voltage up to +1 V.

516 citations

Journal ArticleDOI
TL;DR: In this paper, a method with an accurate control of threshold voltages of AlGaN/GaN high-electron mobility transistors (HEMTs) using a fluoride-based plasma treatment was presented.
Abstract: This paper presents a method with an accurate control of threshold voltages (Vth) of AlGaN/GaN high-electron mobility transistors (HEMTs) using a fluoride-based plasma treatment. Using this method, the Vth of AlGaN/GaN HEMTs can be continuously shifted from -4 V in a conventional depletion-mode (D-mode) AlGaN/GaN HEMT to 0.9 V in an enhancement-mode AlGaN/GaN HEMT. It was found that the plasma-induced damages result in a mobility degradation of two-dimensional electron gas. The damages can be repaired and the mobility can be recovered by a post-gate annealing step at 400 degC. At the same time, the shift in Vth shows a good thermal stability and is not affected by the post-gate annealing. The enhancement-mode HEMTs show a performance (transconductance, cutoff frequencies) comparable to the D-mode HEMTs. Experimental results confirm that the threshold-voltage shift originates from the incorporation of F ions in the AlGaN barrier. In addition, the fluoride-based plasma treatment was also found to be effective in lowering the gate-leakage current, in both forward and reverse bias regions. A physical model of the threshold voltage is proposed to explain the effects of the fluoride-based plasma treatment on AlGaN/GaN HEMTs

489 citations


Additional excerpts

  • ...a fluorine-based plasma treatment of the gate region [55] instead of reducing the AlGaN thickness as in the recessed-gate...

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Journal ArticleDOI
TL;DR: In this article, the GaN-based recessed MIS-gate structure in conjunction with negative polarization charges under the gate allows the high threshold voltage, whereas the low on-state resistance is maintained by the 2D electron gas remaining in the channel except for the recessed gate region.
Abstract: This letter reports normally-off operation of an AlGaN/GaN recessed MIS-gate heterostructure field-effect transistor with a high threshold voltage. The GaN-based recessed MIS-gate structure in conjunction with negative polarization charges under the gate allows us to achieve the high threshold voltage, whereas the low on-state resistance is maintained by the 2-D electron gas remaining in the channel except for the recessed MIS-gate region. The fabricated device exhibits a threshold voltage as high as 5.2 V with a maximum field-effect mobility of 120 cm2/Vmiddots, a maximum drain current of over 200 mA/mm, and a breakdown voltage of 400 V.

383 citations

Journal ArticleDOI
TL;DR: In this paper, a 0.25 μm gate length AlGaN/GaN heterostructure field effect transistor (HFET) with a maximum extrinsic transconductance of 27 mS/mm (at room temperature) limited by the source series resistance was fabricated.
Abstract: We fabricated a 0.25 μm gate length AlGaN/GaN heterostructure field effect transistor (HFET) with a maximum extrinsic transconductance of 27 mS/mm (at room temperature) limited by the source series resistance. The device exhibited an excellent pinch‐off and a low parasitic output conductance in the saturation regime. We measured the cutoff frequency fT and the maximum oscillation frequency fmax as 11 and 35 GHz, respectively. These values are superior to the highest reported values for field effect transistors based on other wide band‐gap semiconductors such as SiC. These results demonstrate an excellent potential of AlGaN/GaN HFETs for microwave and millimeter wave applications.

342 citations

Proceedings ArticleDOI
Yifeng Wu, Marcia Moore, Adam William Saxler1, T. Wisleder, P. Parikh 
26 Jun 2006
TL;DR: In this paper, a double field-plated GaN HEMT with increased power density and robustness was presented, where a first field plate (FP1) was integrated with the gate for both reduced gate resistance and elimination of electron trapping.
Abstract: Field plate technologies have dramatically raised the benchmarks of GaN-based high-electron-mobility transistors (HEMTs). Greater than 30 W/mm power density was demonstrated with gate-connected field plates'. The drawback of additional feedback capacitances added by the field plates was then addressed using source-termination, achieving 21dB large-signal gain and 20-W/mm power density at 4 GHz"l. Recently, multiple field plates were pursued for further improvements""v I. Here we present double field-plated GaN HEMTs with increased power density and robustness. The devices in this study consisted of a Cree HPSI SiC substrate, a 2-4 ptm thick insulating GaN buffer, a thin AlN interlayer and an Al0.26Gao.74N barrier layer. The GaN buffer was doped with Fe for enhanced resistivity and the AlN interlay was included to achieve a high charge-mobility product without the complication of increasing the Al mole fraction of the top AlGaN layer. The device has a first field plate (FP1) integrated with the gate for both reduced gate resistance and elimination of electron trapping. The task of further tailoring the electric field and attaining a higher breakdown voltage is accomplished by a second field plate (FP2), placed on the drain side of the first field plate. FP2 is electrically connected to the source of the HEMT to minimize feedback capacitance. When designed properly, the double field-plated devices can offer a more optimal electric field distribution, improving performance and robustness. Targeting high-power operation at C band, the length of FP1 was set at LF1=0.3-0.5 ptm and FP2 at LF2=0.9-1.2 ptm. The SiN dielectric thickness under FP1 and FP2 was 100 nm and 200 nm, respectively. The device fabrication steps were similar to previous reports,"" except for the gate formation, where the integrated gate and FP1 were deposited on the SiN layer with a previously etched gate opening. Devices of four configurations were fabricated for a direct comparison. Device A had no field plate. Device B had double field plates, both connected to the gate. Device C had double field plates, FP, connected to the gate and FP2 connected to the source. Device D had a single field plate connected to the source. The gate length was about 0.55 ptm and gate-drain separation was 3.5 ptm. Typical devices showed -4 V pinch-off voltage and >1.2 A/mm full channel current. While circuit element extraction from S-parameters revealed practically the same current gain cut-off frequency of 30-35 GHz for the intrinsic devices, the maximum stable gains (MSG) varied based on the extrinsic parasitics. In particular, with LF1=0.3 pim and LF2=0.9 pim, MSG values at 10-GHz and 41 V for devices A, B, C and D were 15.6 dB, 11.2 dB, 16.7 dB and 17.1dB, respectively. It is expected that device B with both field plates connected to the gate has a high feedback capacitance, hence a much lower MSG than the non-field-pate device A. With FP2 connected to the source, however, device C actually exhibited higher MSG than the non-field-pate device. This is attributed to the Faraday shielding effect by the source field plate, which reduces the feedback capacitance. Although device D, with a single field plate connected to the source, showed 0.4-dB higher gain than device C, the less-optimum electric field distribution made it less robust and more prone to degradation at high operation voltages. Power measurements were performed with a load-pull system at 4 GHz. As intended, device C showed the best combination of output power, gain, power-added efficiency and robustness. A 246-pim-wide device with LF1=0.5 pim and LF2=1 .2 pim was able to be biased at 135 V and achieved a continuous-wave (CW) power density of 41.4 W/mm, along with 16-dB associated gain and 60% PAE. This is a significant improvement over previous result of 32.2 W/mm, 14 dB associated gain and 54.8% PAE by single-field-plated GaN HEMTs. Initial reliability tests showed that the double-fieldplated device had no degradation after 100-hour RF operation at 80 V while generating CW output power of 25 W/mm. In summary, a double-field-plate structure has been developed to extend the performance limit of microwave GaN HEMTs. The first field plate offers a high gate conductance and prevents the onset of trapping; while the 2nd field plate maximizes operation voltage without additional feedback capacitances. 41.4 W/mm CW power density was obtained, establishing a new state-of-the-art for microwave devices.

328 citations


"A Survey of Wide Bandgap Power Semi..." refers background in this paper

  • ...1 W/mm in 1996 up to 40 W/mm recently [46]....

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