Proton irradiation-induced traps causing V&lt;inf&gt;T&lt;/inf&gt; instabilities and RF degradation in GaN HEMTs

Sasikumar, A.; Zhang, Z.; Kumar, Pankaj; Zhang, E. X.; Fleetwood, D.M.; Schrimpf, Ronald D.; Saunier, P.; Lee, C.; Ringel, S. A.; Arehart, Aaron R.

doi:10.1109/irps.2015.7112688

Cited by 7 publications

(3 citation statements)

References 26 publications

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“…[21][22][23] From extensive past efforts on GaN, both very deep and shallower defect states have been known to have a major impact on device performance parameters such as threshold voltage, carrier mobility, on-resistance, and DC-to-RF dispersion through trapping effects. [24][25][26] Thus, the knowledge about the presence and the properties of deep level defect states throughout the b-Ga 2 O 3 bandgap of epitaxial materials is likely to be critical for the reliable and high-performance future gallium oxide transistors.…”

Section: Introductionmentioning

confidence: 99%

Deep level defects in Ge-doped (010) β-Ga2O3 layers grown by plasma-assisted molecular beam epitaxy

Farzana

Ahmadi

Speck

et al. 2018

Journal of Applied Physics

104

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Deep level defects were characterized in Ge-doped (010) β-Ga2O3 layers grown by plasma-assisted molecular beam epitaxy (PAMBE) using deep level optical spectroscopy (DLOS) and deep level transient (thermal) spectroscopy (DLTS) applied to Ni/β-Ga2O3:Ge (010) Schottky diodes that displayed Schottky barrier heights of 1.50 eV. DLOS revealed states at EC − 2.00 eV, EC − 3.25 eV, and EC − 4.37 eV with concentrations on the order of 1016 cm−3, and a lower concentration level at EC − 1.27 eV. In contrast to these states within the middle and lower parts of the bandgap probed by DLOS, DLTS measurements revealed much lower concentrations of states within the upper bandgap region at EC − 0.1 – 0.2 eV and EC − 0.98 eV. There was no evidence of the commonly observed trap state at ∼EC − 0.82 eV that has been reported to dominate the DLTS spectrum in substrate materials synthesized by melt-based growth methods such as edge defined film fed growth (EFG) and Czochralski methods [Zhang et al., Appl. Phys. Lett. 108, 052105 (2016) and Irmscher et al., J. Appl. Phys. 110, 063720 (2011)]. This strong sensitivity of defect incorporation on crystal growth method and conditions is unsurprising, which for PAMBE-grown β-Ga2O3:Ge manifests as a relatively “clean” upper part of the bandgap. However, the states at ∼EC − 0.98 eV, EC − 2.00 eV, and EC − 4.37 eV are reminiscent of similar findings from these earlier results on EFG-grown materials, suggesting that possible common sources might also be present irrespective of growth method.

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Section: Introductionmentioning

confidence: 99%

Deep level defects in Ge-doped (010) β-Ga2O3 layers grown by plasma-assisted molecular beam epitaxy

Farzana

Ahmadi

Speck

et al. 2018

Journal of Applied Physics

104

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“…The specific bias conditions, V GS = −2 V and V DS = 2 V, serve as sweet spot for inducing both thermal and electrical stress in the devices. In the OFF state, all device pins were intentionally grounded [6,7,11,17,21,28,[35][36][37]. This configuration was chosen to establish a uniform reference potential and ensure consistency during irradiation.…”

Section: Methodsmentioning

confidence: 99%

Influence of electrical field on the susceptibility of gallium nitride transistors to proton irradiation

Rasel,

Schoell,

Smyth

et al. 2024

J. Phys. D: Appl. Phys.

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Radiation susceptibility of electronic devices is commonly studied as a function of radiation energetics and device physics. Often overlooked is the presence or magnitude of the electrical field, which we hypothesize to play an influential role in low energy radiation. Accordingly, we present a comprehensive study of low-energy proton irradiation on Gallium Nitride High Electron Mobility Transistors (HEMTs), turning the transistor ON or OFF during irradiation. Commercially available GaN HEMTs were exposed to 300 keV proton irradiation at fluences varying from 3.76 x1012 to 3.76x1014 cm-2, and the electrical performance was evaluated in terms of forward saturation current, transconductance, and threshold voltage. The results demonstrate that the presence of an electrical field makes it more susceptible to proton irradiation. The decrease of 12.4% in forward saturation and 19% in transconductance at the lowest fluence in ON mode suggests that both carrier density and mobility are reduced after irradiation. Additionally, a positive shift in threshold voltage (0.32 V and 0.09 V in ON and OFF mode, respectively) indicates the generation of acceptor-like traps due to proton bombardment. HRTEM (High-Resolution Transmission Electron Microscopy) and EDS (Energy Dispersive X-ray Spectroscopy) analysis reveal significant defects introduction and atom intermixing near AlGaN/GaN interfaces and within the GaN layer after the highest irradiation dose employed in this study. According to in-situ Raman spectroscopy, defects caused by irradiation can lead to a rise in self-heating and a considerable increase in (~ 750 times) thermoelastic stress in the GaN layer during device operation. The findings indicate device engineering or electrical biasing protocol must be employed to compensate for radiation-induced defects formed during proton irradiation to improve device durability and reliability.

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“…This behavior is typical of GaN HEMT devices and is consistent with literature reports. [9][10][11] The degradation in saturation current has been attributed to screening of the 2DEG by radiation-induced recombination centers acting as donor traps. 4 In addition, mobility has been shown to be degraded due to scattering induced by roughening of the AlGaN/GaN interface.…”

mentioning

confidence: 99%

Impact of 2 MeV Proton Irradiation on the Large-Signal Performance of Ka-Band GaN HEMTs

Anderson

Meyer

Koehler

et al. 2017

ECS J. Solid State Sci. Technol.

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GaN high electron mobility transistors (HEMTs) have shown the potential to be extremely tolerant of the space radiation environment. To understand whether this radiation tolerance extends to millimeter wave GaN technology nodes, we have investigated the performance of discrete devices made with a commercial Ka-band AlGaN/GaN HEMT process after exposure to 2 MeV proton irradiation. In addition, we evaluate the large signal RF performance to enable the extraction of relevant device metrics (output power, gain, PAE) and understand how this performance compares to existing models for radiation-induced degradation of DC and pulsed I-V parameters.

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Proton irradiation-induced traps causing V<inf>T</inf> instabilities and RF degradation in GaN HEMTs

Cited by 7 publications

References 26 publications

Deep level defects in Ge-doped (010) β-Ga2O3 layers grown by plasma-assisted molecular beam epitaxy

Deep level defects in Ge-doped (010) β-Ga2O3 layers grown by plasma-assisted molecular beam epitaxy

Influence of electrical field on the susceptibility of gallium nitride transistors to proton irradiation

Impact of 2 MeV Proton Irradiation on the Large-Signal Performance of Ka-Band GaN HEMTs

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