Preconditioned BTI on 4H-SiC: Proposal for a Nearly Delay Time-Independent Measurement Technique

Rescher, Gerald; Pobegen, Gregor; Aichinger, Thomas

doi:10.1109/ted.2018.2803283

Cited by 41 publications

(22 citation statements)

References 20 publications

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“…The physics of both negative and positive threshold voltage shifts from NBTI and PBTI is relatively well understood in silicon and SiC MOSFETs as detailed in several papers [1][2][3][4][5][6][7][8][9][10]. Hence, what this paper investigates is the relationship between VTH and VSD for devices that have undergone HTGB stresses, and how measuring VSD can be used to characterize VTH shift from BTI.…”

Section: A Impact Of Bti On the Transfer And Third Quadrant Charactementioning

confidence: 99%

“…Bias Temperature Instability (BTI) is a well-known reliability hazard in SiC MOSFETs. Despite the improvements of the latest generation of SiC power MOSFETs, a survey of recent literature [1][2][3][4][5][6][7][8][9][10] on the subject suggests that it continues to be a topic of concern for both academia and industry. Two factors make it a more intractable problem in SiC: first, the increased density of the traps caused by the presence of carbon atoms during the oxidation of SiC [11] and second, the reduced energy band offsets between the SiC semiconductor and the SiO2 gate insulator [1] (which results from the wider bandgap of SiC compared to silicon).…”

Section: Introductionmentioning

confidence: 99%

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A Novel Non-Intrusive Technique for BTI Characterization in SiC mosfets

Gonzalez

Alatise

2019

IEEE Trans. Power Electron.

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Threshold voltage (VTH) shift due to Bias Temperature Instability (BTI) is a well-known problem in SiC MOSFETs that occurs due to oxide traps in the SiC/SiO2 gate interface. The reduced band offsets and increased interface/fixed oxide traps in SiC MOSFETs makes this a more critical problem compared to silicon. Before qualification, power devices are subjected to gate bias stress tests after which VTH shift is monitored. However, some recovery occurs between the end of the stress and VTH characterization, thereby potentially underestimating the extent of the problem. In applications where the SiC MOSFET module is turned OFF with a negative bias at high temperature, if the VTH shift is severe enough, there may be electrothermal failure due to current crowding since parallel devices lose synchronization during turn-ON. In this paper, a novel method that uses the forward voltage of the body diode during reverse conduction of a small sensing current is introduced as a technique for monitoring VTH shift and recovery due to BTI. This non-invasive method exploits the increased body effect that is peculiar to SiC MOSFETs due to the higher body diode forward voltage. With the proposed method, it is possible to non-invasively assess VTH shift dynamically during BTI characterization tests.

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Section: A Impact Of Bti On the Transfer And Third Quadrant Charactementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A Novel Non-Intrusive Technique for BTI Characterization in SiC mosfets

Gonzalez

Alatise

2019

IEEE Trans. Power Electron.

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“…Some of the difficulties that prevent WBG devices from becoming mainstream are related to concerns such as reliability and specific driver needs. The reliability of SiC MOSFETs is actually plagued by NBTI [1,[4][5][6][7][8] caused mainly by hole trapping in the oxide [2]. This phenomenon affects the operation of the device by shifting its V TH either permanently or in a recoverable manner.…”

Section: • Lower Ronmentioning

confidence: 99%

“…The reason behind this behaviour has been attributed mainly to hole trapping in the oxide near the interface [3][4][5][6][7]. The relatively fast hole traps are filled when a negative bias is applied to the gate.…”

Section: Downmentioning

confidence: 99%

SiC power MOSFETs Threshold-voltage hysteresis and its impact on Short Circuit operation

Asllani¹,

Morel²,

Planson³

et al. 2018

2018 IEEE International Conference on Electrical Systems for Aircraft, Railway, Ship Propulsion and Road Vehicles &Amp; Interna

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TH subthreshold hysteresis is an aspect of MOSFET's threshold instabilities that is gaining interests in last few years. As a matter of fact, reliability concerns are raised due to the fluctuation of the threshold voltage depending on the previous bias state. The subthreshold drain current, also called drain leakage current, is enhanced after a negative gate bias is applied to put the device in OFF-state. This phenomenon affects the static characteristics and might also change the dynamic behaviour of the devices, but such measurements have not yet been reported. This study reports the impact of the Hysteresis on the Short Circuit behaviour of a commercially available SiC MOSFET. A physical interpretation of the measurement is given in order to provide the fundamentals necessary for the evaluation of the reliability of these power devices.

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“…The effect mainly interests sub-threshold bias operational conditions, although some investigations have shown that even above threshold operation can show memory of the preceding bias condition, exactly as a result of the hysteresis of VTH [8], [9]. However, in the context of reliability investigations, the main interest for further investigating such phenomenon is primarily related to the development of SiC-bespoke technology validation tests, able to distinguish between the drift phenomena caused by the electro-thermal stress and the seemingly fully reversible hysteretic behavior [10].…”

mentioning

confidence: 99%

V_TH-Hysteresis and Interface States Characterisation in SiC Power MOSFETs with Planar and Trench Gate

Asllani

Castellazzi

Aviñó-Salvadó

et al. 2019

2019 IEEE International Reliability Physics Symposium (IRPS)

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This paper contributes to investigations on the threshold-voltage (VTH) hysteresis in SiC power MOSFETs. Such effect is of relevance mainly for sub-threshold operation of the devices, but needs to be told apart from stress-related VTHdrift phenomena for technology maturity and reliability validation goals. Important differences exist in commercially available devices, particularly in relation to their gate technology, planar or trench, the latter also showing a marked temperature dependence of the hysteretic range. Based on the experimental characterization of the interface capacitance and charge, this paper puts forward a methodology for determining the types of traps affecting the various devices, with the aim of contributing a tool to assist driving of technological maturity in future generation devices. This paper also shows the potential of capacitance hysteresis measurement to the estimation of the distribution of interface.

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Preconditioned BTI on 4H-SiC: Proposal for a Nearly Delay Time-Independent Measurement Technique

Cited by 41 publications

References 20 publications

A Novel Non-Intrusive Technique for BTI Characterization in SiC mosfets

A Novel Non-Intrusive Technique for BTI Characterization in SiC mosfets

SiC power MOSFETs Threshold-voltage hysteresis and its impact on Short Circuit operation

V_TH-Hysteresis and Interface States Characterisation in SiC Power MOSFETs with Planar and Trench Gate

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Preconditioned BTI on 4H-SiC: Proposal for a Nearly Delay Time-Independent Measurement Technique

Cited by 41 publications

References 20 publications

A Novel Non-Intrusive Technique for BTI Characterization in SiC mosfets

A Novel Non-Intrusive Technique for BTI Characterization in SiC mosfets

SiC power MOSFETs Threshold-voltage hysteresis and its impact on Short Circuit operation

VTH-Hysteresis and Interface States Characterisation in SiC Power MOSFETs with Planar and Trench Gate

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Product

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V_TH-Hysteresis and Interface States Characterisation in SiC Power MOSFETs with Planar and Trench Gate