Vertical GaN Fin JFET: A Power Device with Short Circuit Robustness at Avalanche Breakdown Voltage

Zhang, R.; Liu, J.; Li, Q.; Pidaparthi, Subhash; Edwards, Andrew; Drowley, Cliff; Zhang, Y.

doi:10.1109/irps48227.2022.9764569

Cited by 12 publications

(7 citation statements)

References 36 publications

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“…In addition to under the short-circuit stress, the vertical GaN Fin-JFET was also found to exhibit a failure-toopen-circuit (FTO) signature under the through-fin avalanche (29). This FTO signature is desirable for system applications, at the same time, very interesting from the device physics standpoint, as in prior literature all Si and SiC power transistors were reported to show a failure-to-short-circuit (FTS) signature under the avalanche condition (29) with most of them showing a FTS signature under the short circuit condition (28). The detailed works on understanding the unique FTO signature of vertical GaN Fin-JFETs under the through-fin avalanche and short-circuit conditions are presented in ( 29) and (28), respectively.…”

Section: Failure-to-open-circuit Signaturementioning

confidence: 75%

(Invited) Breakthrough Avalanche and Short Circuit Robustness in Vertical GaN Power Devices

Zhang¹,

Zhang²,

Song³

et al. 2022

ECS Trans.

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Power devices are highly desirable to possess excellent avalanche and short-circuit (or surge-current) robustness for numerous power electronics applications like automotive powertrains, electric grids, motor drives, among many others. Current commercial GaN power device, the lateral GaN high-electron-mobility transistor (HEMT), is known to have no avalanche capability and very limited short-circuit robustness. These limitations have become a roadblock for penetration of GaN devices in many industrial power applications. Recently, through collaborations with NexGen Power Systems (NexGen), Inc., we have demonstrated breakthrough avalanche, surge-current and short-circuit robustness in NexGen’s vertical GaN p-n diodes and fin-shape junction-gate field-effect-transistors (Fin-JFETs). These large-area GaN diodes and Fin-JFETs were manufactured in NexGen’s 100 mm GaN-on-GaN fab. The demonstrated avalanche, surge-current and short-circuit capabilities are comparable or even superior to Si and SiC power devices. Additionally, vertical GaN Fin-JFETs were found to fail to open-circuit under avalanche and short-circuit conditions, which is highly desirable for the system safety. This talk reviews the key robustness results of vertical GaN power devices and unveils the enabling device physics. Fundamentally, these results signify that, in contrast to some popular belief, GaN devices with appropriate designs can achieve excellent robustness and thereby encounter no barriers for applications in electric vehicles, grids, renewable processing, and industrial motor drives.

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Section: Failure-to-open-circuit Signaturementioning

confidence: 75%

(Invited) Breakthrough Avalanche and Short Circuit Robustness in Vertical GaN Power Devices

Zhang¹,

Zhang²,

Song³

et al. 2022

ECS Trans.

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“…The underlying device physics that enables a short-circuit capability at BV AVA is also found to be the 'avalanche through fin', as illustrated in Fig. 15(c) [166]. In this condition, the thermal (I AVA ) stress is mainly located at the fin channel, which is separated from the main blocking junction below the p-GaN gate that supports BV AVA .…”

Section: Emerging Vertical Gan Devicementioning

confidence: 86%

“…This approach enables a tSC over 3 µs in industrial Cascode GaN HEMTs. A more significant improvement is demonstrated in 600-700 V vertical GaN FETs, with a t SC over 30 µs at 400 V [147], [165], [166]. This vertical GaN FET will be elaborated in Section VII.…”

Section: A Short Circuit Robustnessmentioning

confidence: 94%

Stability, Reliability, and Robustness of GaN Power Devices: A Review

Kozak

Zhang

Porter

et al. 2023

IEEE Trans. Power Electron.

109

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Gallium nitride (GaN) devices are revolutionarily advancing the efficiency, frequency, and form factor of power electronics. However, the material composition, architecture and physics of many GaN devices are significantly different from silicon and silicon carbide devices. These distinctions result in many unique stability, reliability and robustness issues facing GaN power devices. This paper reviews the current understanding of these issues, particularly those related to dynamic switching, and their impacts on system performance. Instead of delving into reliability physics, this paper intends to provide power electronics engineers the necessary information for deploying GaN devices in existing and emerging applications, as well as provide references for the qualification evaluations of GaN power devices. The issues covered in this paper include the dynamic instability of device parameters (e.g., on-resistance, threshold voltage, output capacitance), the device robustness in avalanche, overvoltage and short-circuit conditions, the device's switching reliability and lifetime, as well as the device's ruggedness under radiation and extreme (cryogenic and elevated) temperatures. Knowledge gaps and immediate research opportunities in the relevant fields are also discussed. 1

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“…103) The capability of accommodating a high channel current also produces a good shortcircuit ruggedness of GaN Fin-JFETs at BV AVA . 28,105,106) The viability to accommodate two avalanche paths modulated by the gate driver is the inherent property of power JFETs and not a feature specific to GaN. By tuning the gate driver design (e.g.…”

Section: Key Device Design For Avalanche Breakdownmentioning

confidence: 99%

Power device breakdown mechanism and characterization: review and perspective

Zhang

2023

Jpn. J. Appl. Phys.

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Breakdown voltage (BV) is arguably one of the most critical parameters for power devices. While avalanche breakdown is prevailing in silicon and silicon carbide devices, it is lacking in many wide bandgap (WBG) and ultra-wide bandgap (UWBG) devices, such as the gallium nitride high electron mobility transistor, due to the deployment of junction-less device structures or the inherent material challenges of forming p-n junctions. This paper starts with a survey of avalanche and non-avalanche breakdown mechanisms, followed by the distinction between the static and dynamic BV. Various BV characterization methods, including the static and pulse I-V sweep, unclamped and clamped inductive switching, as well as continuous overvoltage switching, are comparatively introduced. The device physics behind the time- and frequency-dependent BV as well as the enabling device structures for avalanche breakdown are also discussed. The paper concludes by identifying research gaps for understanding the breakdown of WBG and UWBG power devices.

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Vertical GaN Fin JFET: A Power Device with Short Circuit Robustness at Avalanche Breakdown Voltage

Cited by 12 publications

References 36 publications

(Invited) Breakthrough Avalanche and Short Circuit Robustness in Vertical GaN Power Devices

(Invited) Breakthrough Avalanche and Short Circuit Robustness in Vertical GaN Power Devices

Stability, Reliability, and Robustness of GaN Power Devices: A Review

Power device breakdown mechanism and characterization: review and perspective

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