Traps localization and analysis in GaN HEMTs

Chini, Alessandro; Soci, Fabio; Meneghesso, Gaudenzio; Meneghini, Matteo; Zanoni, Enrico

doi:10.1016/j.microrel.2014.07.085

Cited by 9 publications

(7 citation statements)

References 11 publications

(13 reference statements)

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“…The linear fit of the points on the Arrhenius plot yielded a 0.52 eV activation energy and 5 x 10 -16 cm 2 cross section, which are consistent with values reported in the literature for Fe-related buffer traps [7][8][9][10][11][12]. To better identify the trap type, we compared the Arrhenius plot obtained in this work, with those obtained in previous reports and associated with Fe-traps [8,11,12,[28][29][30], see Fig. 7.…”

Section: Device Description and Preliminary Characterizationsupporting

confidence: 86%

“…Furthermore, the trap-filling pulse parameters were chosen to deliberately induce a relatively small current variation (~4 mA/mm) to avoid excessive perturbation of the steady-state operating point. This choice was mainly motivated by the following considerations: i) a large current variation would change significantly the dissipated power during the monitored transient [17], whereas a small perturbation does not affect the power set in steady-state condition, thus yielding negligible temperature variations; ii) a small current variation is representative of a low amount of trapped charge variation [30][31][32], whose dynamics is expected to not significantly alter the electric field profile during the DCT.…”

Section: A) Choice Of the Bias Conditionsmentioning

confidence: 99%

“…Equivalently to Section II, during the short filling pulse (1 µs), the devices are biased at VGS,pulse=-3.8 V, i.e., 1 V below DUT's VTH, so that the subthreshold current flowing through the channel/buffer provides the electrons to be trapped [30] and just the Fe-traps response is induced. The VDS,pulse level is instead adjusted for each DCT in order to induce a constant amplitude in the dID/dlog10t peak for all the acquired DCTs.…”

Section: A) Choice Of the Bias Conditionsmentioning

confidence: 99%

“…This choice was adopted to ensure the same variation of trapped charge into buffer states. In fact, since the amplitude of the peak is related to the amount of current dispersion caused by the trap with the considered time constant [30], i.e., to the amount of trapped electrons [31,32], maintaining a constant peak amplitude ensures a constant variation of trapped charge during the filling pulse, regardless of the steady state bias.…”

Section: A) Choice Of the Bias Conditionsmentioning

confidence: 99%

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Electric Field and Self-Heating Effects on the Emission Time of Iron Traps in GaN HEMTs

Cioni

Zagni

Selmi

et al. 2021

IEEE Trans. Electron Devices

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In this paper we separately investigate the role of electric field and device self-heating (SHE) in enhancing the charge emission process from Fe-related buffer traps (0.52 eV from Ec) in AlGaN/GaN High Electron Mobility Transistors (HEMTs). The experimental analysis was performed by means of Drain Current Transient (DCT) measurements for either i) different dissipated power (PD,steady) at constant drain-to-source bias (VDS,steady) or ii) constant PD,steady at different VDS,steady. We found that i) an increase in PD,steady yields an acceleration in the thermally activated emission process, consistently with the temperature rise induced by SHE. On the other hand, ii) the field effect turned out to be negligible within the investigated voltage range, indicating the absence of Poole-Frenkel effect (PFE). A qualitative analysis based on the electric field values obtained by numerical simulations is then presented to support the interpretation and conclusions.

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Section: Device Description and Preliminary Characterizationsupporting

confidence: 86%

Section: A) Choice Of the Bias Conditionsmentioning

confidence: 99%

Section: A) Choice Of the Bias Conditionsmentioning

confidence: 99%

Section: A) Choice Of the Bias Conditionsmentioning

confidence: 99%

See 2 more Smart Citations

Electric Field and Self-Heating Effects on the Emission Time of Iron Traps in GaN HEMTs

Cioni

Zagni

Selmi

et al. 2021

IEEE Trans. Electron Devices

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“…Since trap filling condition strongly depend on the applied voltages, comparing pulsed I-V obtained at different quiescent bias points quickly allows to evaluate the presence and in some way the amount of trapping phenomena. A typical set of pulsed I-V is performed by comparing at least three or more different quiescent bias points [390], [468], [469]: (i) the VGS=0 V,VDS=0 V QBP, which sets also the reference of the "fresh" device conditions; (ii) gate-lag effect is then evaluated with a QBP where VGS is held below the device threshold voltage and VDS=0 V; (iii) drain-lag effect is finally evaluated by a QBP with the device in off-state conditions and large VDS. Obviously, many other combinations can be considered by the three reported are the most used for device characterization.…”

Section: Pulsed IVmentioning

confidence: 99%

GaN-based power devices: Physics, reliability, and perspectives

Meneghini

Santi

Abid

et al. 2021

Journal of Applied Physics

298

126

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Over the last decade, gallium nitride has emerged as an excellent material for the fabrication of power devices. Among the semiconductors for which power devices are already available on the market, GaN has the widest energy gap, the largest critical field, the highest saturation velocity, thus representing an excellent material for the fabrication of high speed/high voltage components.The presence of spontaneous and piezoelectric polarization allows to create a 2-dimensional electron gas, with high mobility and large channel density, in absence of any doping, thanks to the use of AlGaN/GaN heterostructures. This contributes to minimize resistive losses; at the same time, for GaN transistors switching losses are very low, thanks to the small parasitic capacitances and switching charges. Device scaling and monolithic integration enable high frequency operation, with consequent advantages in terms of miniaturization.For high power/high voltage operation, vertical device architectures are being proposed and investigated, and 3-dimensional structuresfin-shaped, trench-structured, nanowire-basedare demonstrating a great potential. Contrary to silicon, GaN is a relatively young material: trapping and degradation processes must be understood and described in detail, with the aim of optimizing device stability and reliability. This tutorial paper describes the physics, technology and reliability of GaN-based power devices: in the first part of the article, starting from a discussion of the main properties of the material, the characteristics of lateral and vertical GaN transistors are discussed in detail, to provide guidance in this complex and interesting field. The second part of the paper focuses on trapping and reliability aspects: the physical origin of traps in GaN, and the main degradation mechanisms are discussed in detail. The wide set of referenced papers and the insight on the most relevant aspects gives the reader a comprehensive overview on present and next-generation GaN electronics. IntroductionOver the past decade, gallium nitride has emerged as an excellent material for the fabrication of power semiconductor devices. Thanks to the unique properties of GaN, diodes and transistors based on this material have excellent performance, compared to their silicon counterparts, and are expected to find wide application in the next-generation power converters. Owing to the flexibility and the energy efficiency of GaN-based power converters, the interest towards this technology is rapidly growing: the aim of this tutorial is to review the most relevant physical properties, the operating principles, the fabrication parameters, and the stability/reliability issues of GaN-based power transistors. For introductory purposes, we start summarizing the physical reasons why GaN transistors achieve a much better performance than the corresponding silicon devices, to help the reader understanding the unique advantages of this technology.The properties of GaN devices allow the fabrication of high-efficiency (near or above 99 %)...

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