Parasitic effects and traps in AlGaN/GaN HEMT on sapphire substrate

Fathallah, Olfa; Gassoumi, M.; Grimbert, B.; Gaquière, C.; Maâref, H.

doi:10.1051/epjap/2010085

Cited by 11 publications

(4 citation statements)

References 22 publications

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“…In studies of n-GaN grown by MOCVD, a deep levels E 3 , E 4 and we assume also level E 1 with activation energy ~ 0.14 eV were observed in GaN grown using trimethylgallium (TMGa); when TMGa was replaced by triethylgallium (TEGa), the E 1, E 3 , E 4 levels were no longer detectable by DLTS. This was interpreted as suggesting that the 0.14 eV and E 3 , E 4 levels may be related to carbon or hydrogen atoms that may be incorporated from the methyl radicals during growth [14,15]. In comparing DLTS measurements from samples grown by different techniques, it would not be unexpected for electronic levels arising from native defects to be observed in GaN growth by a variety of techniques; conversely, the presence and concentration of defect levels associated with impurities might be expected to vary in material grown by different techniques.…”

Section: Resultsmentioning

confidence: 99%

Point Defects in Chemical-Vapor Deposited Diamond, High-Purity Semi-Insulating SiC, and Epitaxial GaN

et al. 2012

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The native and impurity induced point defects in undoped chemical-vapor deposited diamond, high-purity semi-insulating SiC and grown by molecular beam epitaxy GaN were investigated by isothermal charge-based deep level transient spectroscopy (Q-DLTS). It was found that deep levels in undoped diamond have a continuous energy spectrum with two maximums at energies 0.71 and 0.54 eV. Several discrete deep levels were found in SiC. Defect level E1 is attributed to atom displacement on the carbon sublattice in SiC. Levels E2, E4 are related to (Vc -Vsi) complex and silicon vacancy Vsi, respectively. Obtained values of activetion energy and capture cross-section allow expecting that deep level E3 associated with the carbon vacancy Vc, while acceptor level En is vanadium-induced level. Eight deep levels were observed in GaN. Levels E1, E2, E7, and E8 have been observed in low doped n-GaN are characterized for the first time in our studies.

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Section: Resultsmentioning

confidence: 99%

Point Defects in Chemical-Vapor Deposited Diamond, High-Purity Semi-Insulating SiC, and Epitaxial GaN

et al. 2012

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“…7,8 Therefore, it is necessary to perform basic investigations of deep level defects in AlGaN/GaN heterostructures. To date, a number of researchers have investigated the deep level defects in AlGaN/GaN heterostructures using various characterization techniques, such as photo-ionization spectroscopy, 9 chargebased deep level transient spectroscopy (QDLTS), 10 deep level optical spectroscopy (DLOS), 11 current deep level tran-sient spectroscopy (CDLTS), 12,13 and deep level transient spectroscopy (DLTS). 14,15 In previous work, 15 we had started the study of the Al 0.25 Ga 0.75 N/GaN/SiC structure by realizing Ig(Vg), C(V) and capacitance DLTS measurements on the (Ni/Au) Al 0.25 Ga 0.75 N/GaN/SiC Schottky barrier diode because it is very crucial to understand the influence of defects on the carrier transport in such heterostructures.…”

Section: Introductionmentioning

confidence: 99%

Anomaly and defects characterization by I-V and current deep level transient spectroscopy of Al0.25Ga0.75N/GaN/SiC high electron-mobility transistors

Saadaoui

Salem

Gassoumi

et al. 2012

Journal of Applied Physics

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In this paper, we report static electric drain-source current-voltage measurements for different gate voltages and at different temperatures, performed on Al0.25Ga0.75N/GaN/SiC high electron-mobility transistors (HEMT). The results show the presence of kink and collapse effects. We have demonstrated that these effects are significant in the temperature range varying from 150 to 400 K with a maximum around 300 K. This parasitic effect was correlated with the presence of deep levels in our transistor. Indeed, we have noticed the presence of two electron traps named A1 and A2, and one hole trap named H1; their respective activation energies, which are determined using current deep level transient spectroscopy (CDLTS), are, respectively, 0.56, 0.82, and 0.75 eV. Traps H1 and A1 are shown to be extended defects in the Al0.25Ga0.75N/GaN heterostructure; they are supposed to be the origin of the kink and collapse effects. However, the punctual defect A2 seems to be located either in the free gate-drain surface, in the metal/AlGaN interface, or in the AlGaN/GaN interface.

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“…12,13) The electron injection into deep traps suppresses the leakage current due to a low probability of electron detrapping into conduction band. 14) However, the electron injection into deep traps causes a transient delay which is called by current collapse. 15) We have already reported the low drain leakage current of 20 nA/mm and the high breakdown voltage of 1140 V by employing O 2 annealing on AlGaN/GaN HEMTs on 4H-SiC substrate.…”

Section: Introductionmentioning

confidence: 99%

“…Ga 2 O 3 layer which is sandwiched by Al 2 O 3 acts as charge accumulation center due to the unintentionally formed Ga-vacancies. 14) The accumulated electrons in Ga 2 O 3 layer under the reverse bias deplete the electrons in bulk and 2DEG so that breakdown voltage and V TH are increased.…”

Section: Introductionmentioning

confidence: 99%

New AlGaN/GaN High Electron Mobility Transistors Employing Charge Accumulation in Multiple Al₂O₃/Ga₂O₃Stacks

Seok

Ahn

Han

et al. 2012

Jpn. J. Appl. Phys.

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We have proposed and fabricated new AlGaN/GaN high electron mobility transistors (HEMTs) employing charge accumulation in multiple Al2O3/Ga2O3 stacks by rf-sputtering in order to increase the breakdown voltage and the threshold voltage (V TH). 10-nm-thick rf-sputtered Al2O3/Ga2O3 stacks on the GaN cap, which consist of 2-nm-thick Al2O3 and 2-nm-thick Ga2O3, would induce accumulation of electrons and holes in the stacks on AlGaN/GaN HEMTs. The proposed device achieves the high breakdown voltage of 1104 V while the unpassivated one shows the low breakdown voltage of 380 V. The drain leakage current is considerably suppressed from 654 µA/mm to 33 nA/mm. The V TH of the proposed device is -1.4 V while that of the conventional device is -2 V due to the accumulated electrons in the multiple Al2O3/Ga2O3 stacks. We have also investigated the charge accumulation phenomena by applying the negative DC stress to the proposed device with and without final SiO2 passivation, respectively.

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Parasitic effects and traps in AlGaN/GaN HEMT on sapphire substrate

Cited by 11 publications

References 22 publications

Point Defects in Chemical-Vapor Deposited Diamond, High-Purity Semi-Insulating SiC, and Epitaxial GaN

Point Defects in Chemical-Vapor Deposited Diamond, High-Purity Semi-Insulating SiC, and Epitaxial GaN

Anomaly and defects characterization by I-V and current deep level transient spectroscopy of Al0.25Ga0.75N/GaN/SiC high electron-mobility transistors

New AlGaN/GaN High Electron Mobility Transistors Employing Charge Accumulation in Multiple Al₂O₃/Ga₂O₃Stacks

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Parasitic effects and traps in AlGaN/GaN HEMT on sapphire substrate

Cited by 11 publications

References 22 publications

Point Defects in Chemical-Vapor Deposited Diamond, High-Purity Semi-Insulating SiC, and Epitaxial GaN

Point Defects in Chemical-Vapor Deposited Diamond, High-Purity Semi-Insulating SiC, and Epitaxial GaN

Anomaly and defects characterization by I-V and current deep level transient spectroscopy of Al0.25Ga0.75N/GaN/SiC high electron-mobility transistors

New AlGaN/GaN High Electron Mobility Transistors Employing Charge Accumulation in Multiple Al2O3/Ga2O3Stacks

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New AlGaN/GaN High Electron Mobility Transistors Employing Charge Accumulation in Multiple Al₂O₃/Ga₂O₃Stacks