Detection of Mobile Ions in the Presence of Charge Trapping in SiC MOS Devices

Habersat, Daniel B.; Lelis, Aivars J.; Green, Ronald

doi:10.4028/www.scientific.net/msf.717-720.461

Cited by 15 publications

(15 citation statements)

References 10 publications

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“…V fb hysteresis presents a counterclockwise characteristic contrary to the shift behavior at LT because of the positive shift induced by NBTS and the negative shift caused by PBTS. Similar to the explanation above, this instability behavior can be attributed to HT-activated mobile ions in SiO 2 , countering the effect of charge trapping [27,47].…”

Section: Stress Conditionssupporting

confidence: 67%

“…This result may be due to the introduction of mobile ions the gate oxide. These mobile ions can be activated and mobilized at an increased temperature, thereby causing an opposite effect of charge trapping in the interfacial region [41,47]. The accelerated V th recovery at HT is another possible explanation.…”

Section: Stress Conditionsmentioning

confidence: 99%

“…However, mobile ions exist in SiC MOSFETs [28,43,46]. The movement toward and away from the SiC/SiO 2 interface of mobile ions under BTS results in V th instability [47,77]. In contrast to the shift feature of charge trapping, instability features caused by mobile ions are negative V th shift under PBTS, positive V th shift under NBTS, and counterclockwise C-V hysteresis [27,43].…”

Section: Mobile Ionsmentioning

confidence: 99%

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Bias temperature instability in SiC metal oxide semiconductor devices

Yang¹,

Wei²,

Wang³

2021

J. Phys. D: Appl. Phys.

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Although silicon carbide (SiC) metal oxide semiconductor field-effect transistors (MOSFETs) are commercially available, bias temperature instability (BTI) defined as shifts in V th in SiC MOSFET and V fb in MOS capacitor after the device is operated at a high temperature, seriously affects device reliability and limits further commercial applications. These instabilities are mainly attributed to charge trapping at and near the SiC/SiO 2 interface and mobile ions in a gate oxide. The consequences of V th instability are serious and can worsen the performance and lifetime of SiC MOS devices. In this review, the SiC/SiO 2 interface issue is introduced, and BTI occurring in current SiC MOS devices is described in detail. V th /V fb instability behavior induced by measurement and stress conditions, microscopic defects and instability mechanisms, recent measurement techniques of near-interfacial oxide traps, and BTI improvement resulting from the fabrication processes are described. BTI improvement mainly involves the control of charge trapping and movements of ions. The fabrication processes are related to oxidation and pre-and post-oxidation treatments. This review can help deepen our understanding of BTI and reduce its influence on SiC MOS devices performance.

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Section: Stress Conditionssupporting

confidence: 67%

Section: Stress Conditionsmentioning

confidence: 99%

Section: Mobile Ionsmentioning

confidence: 99%

See 1 more Smart Citation

Bias temperature instability in SiC metal oxide semiconductor devices

Yang¹,

Wei²,

Wang³

2021

J. Phys. D: Appl. Phys.

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“…It has been suggested that the origin of the flatband shift is due to the charge injection from the SiC substrate into the oxide [28]. Recently, mobile charge has been detected by triangular voltage sweep (TVS) measurements and this has been identified as the cause of the instability of SiC MOS devices at elevated temperatures [29]. Nevertheless, the intrinsic mobile charge in the oxidised SiC MOS capacitors can be reduced or increased by means of the post-oxide annealing treatment [28].…”

Section: Introductionmentioning

confidence: 99%

Positive flatband voltage shift in phosphorus doped SiO₂/N-type 4H-SiC MOS capacitors under high field electron injection

Idris

Weng

Peters

et al. 2019

J. Phys. D: Appl. Phys.

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The effect of phosphorus inclusion on different bias stress at high electric field on phosphorus doped SiO 2 is investigated by electrical measurements of SiC MOS capacitors. 1 MHz C − V measurements with (1) different bias hold time (up to 999 s at room and high temperature of 250 • C), (2) different applied gate voltage (± 10, 20 and 30 V without stress time) and (3) different bias hold time at high voltage (± 30 V) were taken to observe the evolution of flatband voltage, effective oxide charge density and interface state density. In this investigation, the characteristics were measured in both sweep directions and compared to those obtained from undoped SiO 2 samples. At 250 • C, the flatband voltage of phosphorus-doped SiO 2 samples shows a significant shift to the positive with increasing bias hold time. Similar trends are observed with the characteristics obtained at room temperature, but the shifts are less significant. Both undoped and phosphorus-doped samples show positive flatband shift when a higher bias was applied for longer hold times, but the latter demonstrated more significant changes. We conclude that the phosphorus ions increase the instability of the electrical characteristics related to the generation of mobile charges in the SiO 2 , resulting in the injection of electrons from the semiconductor to the oxide. Therefore, the accumulated negative charge in phosphorus-doped SiO 2 resulting from the injection of electrons, which is enhanced by the mobile charge, is responsible for the enhanced positive shift in C − V and I − V characteristics.

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“…Socalled fast and ultra-fast V T measurement techniques have also been utilized for structures where V T has been reduced and more sensitivity is required [12], [13]. It is widely understood and accepted that the drift is due to the well-known charge trapping phenomena at or adjacent to the SiC-SiO2 interface [14] while some researchers suspect there could still be some contribution from mobile ions [15], as was the case for early Si devices [16].…”

Section: Introductionmentioning

confidence: 99%

Characteristics and aging of SiC MOSFETs operated at very high temperatures

et al. 2014

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Silicon carbide power devices are purported to be capable of operating at very high temperatures. Current commercially available SiC MOSFETs from a number of manufacturers have been evaluated to understand and quantify the aging processes and temperature dependencies that occur when operated up to 350°C. High temperature constant positive bias stress tests demonstrated a two times increase in threshold voltage from the original value for some device types, which was maintained indefinitely but could be corrected with a long negative gate bias. The threshold voltages were found to decrease close to zero and the on-state resistances increased quite linearly to approximately five or six times their room temperature values. Long term thermal aging of the dies appears to demonstrate possible degradation of the ohmic contacts. This appears as a rectifying response in the I-V curves at low drain-source bias. The high temperature capability of the latest generations of these devices has been proven independently; provided that threshold voltage management is implemented, the devices are capable of being operated and are free from the effects of thermal aging for at least 70 hours cumulative at 300°C.

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Detection of Mobile Ions in the Presence of Charge Trapping in SiC MOS Devices

Cited by 15 publications

References 10 publications

Bias temperature instability in SiC metal oxide semiconductor devices

Bias temperature instability in SiC metal oxide semiconductor devices

Positive flatband voltage shift in phosphorus doped SiO₂/N-type 4H-SiC MOS capacitors under high field electron injection

Characteristics and aging of SiC MOSFETs operated at very high temperatures

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Detection of Mobile Ions in the Presence of Charge Trapping in SiC MOS Devices

Cited by 15 publications

References 10 publications

Bias temperature instability in SiC metal oxide semiconductor devices

Bias temperature instability in SiC metal oxide semiconductor devices

Positive flatband voltage shift in phosphorus doped SiO2/N-type 4H-SiC MOS capacitors under high field electron injection

Characteristics and aging of SiC MOSFETs operated at very high temperatures

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Product

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Positive flatband voltage shift in phosphorus doped SiO₂/N-type 4H-SiC MOS capacitors under high field electron injection