Direct comparison of traps in InAlN/GaN and AlGaN/GaN high electron mobility transistors using constant drain current deep level transient spectroscopy

Sasikumar, A.; Arehart, Aaron R.; Martin-Horcajo, Sara; Romero, M. F.; Pei, Yutao; Brown, David F.; Recht, F.; Forte-Poisson, M.A. di; Calle, F.; Tadjer, Marko J.; Keller, S.; DenBaars, Steven P.; Mishra, Umesh K.; Ringel, S. A.

doi:10.1063/1.4813862

Cited by 54 publications

(54 citation statements)

References 25 publications

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“…For proton-irradiation at 1.8 MeV, both AlGaN/GaN and AlGaN/AlN/GaN HEMTs showed significant degradation, around 40% drain current reduction, 22,24 after the devices were exposed to protons at a dose of 10 14 cm −2 . Sasikumar et al 71 have identified two main levels as being responsible for the threshold voltage shifts in irradiated AlGaN/GaN HEMTs, namely at E C −0.3.25 eV and at E C −0.1.25 eV. The latter is possibly the nitrogen interstitial defect, while the former is not firmly identified.…”

Section: Changes In Gan-based Hemt Performance After Irradiationmentioning

confidence: 99%

“…Similarly, the V Ga defect may be listed as having an energy level of E C −2.5 eV, which is equivalent to the E V +1.0 eV value discussed earlier. 56,57,71 Most of the changes in GaN due to proton or electron damage can be understood in terms of introduction of these primary point defects and for example, the carrier removal rate in GaN for light particles is well accounted for by the introduction of these simple defects. At higher doses or when the GaN contains high levels of dopants or other impurities, complexes involving the primary radiation damage defects and these other impurities can occur and the situation becomes more complicated.…”

Section: Defects In Gan After Irradiationmentioning

confidence: 99%

“…91 Coming back to the point that radiation exposure increases the concentration of defects already present in the GaN, Figure 16 shows a schematic representation of energy levels in the gap of both n-and p-type GaN before and after proton irradiation. 71,78 Note how many of the defects already present in the material increase after proton irradiation. Figure 17 provides a summary of the carrier removal rates in n-and p-GaN films, and InAlN/GaN and AlGaN/GaN HEMT structures exposed to proton, electron, neutron or gamma-ray fluences at different energies.…”

mentioning

confidence: 99%

“…In p-GaN implanted with 100 keV protons, degradation of luminescent and properties starts at doses ∼10 12 cm −2 , while decreases in hole concentration were evident for Figure 16. Schematic of position in the bandgap of defects in n-and p-GaN before and after proton irradiation (after Sasikumar et al 71,78 Both threshold doses are more than an order of magnitude lower than in proton implanted n-GaN and may involve complex formation between the radiation defects and Mg acceptors. The main deep centers introduced by proton damage in pGaN have activation energies 0.3 eV, 0.6 eV and 0.9 eV.…”

mentioning

confidence: 99%

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Review—Ionizing Radiation Damage Effects on GaN Devices

Pearton

Ren

Patrick

et al. 2015

ECS J. Solid State Sci. Technol.

282

130

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Gallium Nitride based high electron mobility transistors (HEMTs) are attractive for use in high power and high frequency applications, with higher breakdown voltages and two dimensional electron gas (2DEG) density compared to their GaAs counterparts. Specific applications for nitride HEMTs include air, land and satellite based communications and phased array radar. Highly efficient GaNbased blue light emitting diodes (LEDs) employ AlGaN and InGaN alloys with different compositions integrated into heterojunctions and quantum wells. The realization of these blue LEDs has led to white light sources, in which a blue LED is used to excite a phosphor material; light is then emitted in the yellow spectral range, which, combined with the blue light, appears as white. Alternatively, multiple LEDs of red, green and blue can be used together. Both of these technologies are used in high-efficiency white electroluminescent light sources. These light sources are efficient and long-lived and are therefore replacing incandescent and fluorescent lamps for general lighting purposes. Since lighting represents 20-30% of electrical energy consumption, and because GaN white light LEDs require ten times less energy than ordinary light bulbs, the use of efficient blue LEDs leads to significant energy savings. GaN-based devices are more radiation hard than their Si and GaAs counterparts due to the high bond strength in III-nitride materials. The response of GaN to radiation damage is a function of radiation type, dose and energy, as well as the carrier density, impurity content and dislocation density in the GaN. The latter can act as sinks for created defects and parameters such as the carrier removal rate due to trapping of carriers into radiation-induced defects depends on the crystal growth method used to grow the GaN layers. The growth method has a clear effect on radiation response beyond the carrier type and radiation source. We review data on the radiation resistance of AlGaN/GaN and InAlN/GaN HEMTs and GaN-based LEDs to different types of ionizing radiation, and discuss ion stopping mechanisms. The primary energy levels introduced by different forms of radiation, carrier removal rates and role of existing defects in GaN are discussed. The carrier removal rates are a function of initial carrier concentration and dose but not of dose rate or hydrogen concentration in the nitride material grown by Metal Organic Chemical Vapor Deposition. Proton and electron irradiation damage in HEMTs creates positive threshold voltage shifts due to a decrease in the two dimensional electron gas concentration resulting from electron trapping at defect sites, as well as a decrease in carrier mobility and degradation of drain current and transconductance. State-of-art simulators now provide accurate predictions for the observed changes in radiation-damaged HEMT performance. Neutron irradiation creates more extended damage regions and at high doses leads to Fermi level pinning while 60 Co γ-ray irradiation leads to much smaller changes in HEMT drain ...

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Section: Changes In Gan-based Hemt Performance After Irradiationmentioning

confidence: 99%

Section: Defects In Gan After Irradiationmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Review—Ionizing Radiation Damage Effects on GaN Devices

Pearton

Ren

Patrick

et al. 2015

ECS J. Solid State Sci. Technol.

282

130

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“…17 The increased density of deeper trap levels increases scattering leading to shorter L. The extended defects generated in the buffer layer can be responsible for changes in dc properties including increases in gate leakage current. 28,35 The effectiveness of annealing for gamma induced defect mitigation has been explored in Ref. 33.…”

mentioning

confidence: 99%

Effects of Gamma Irradiation on AlGaN-Based High Electron Mobility Transistors

Lee

Flitsiyan

Chernyak

et al. 2017

ECS J. Solid State Sci. Technol.

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The influence of various radiations on the performance and carrier transport properties of AlGaN/GaN HEMTs have been observed at length over the previous few decades. Gamma irradiation has been shown to have little influence on carrier density but has significant effects on device performance. The effects of gamma irradiation have proven non-monotonic in nature, dividing results into low and high doses with an inflection point near 300 Gy. Low doses of gamma irradiation have a tendency to improve device characteristics, while high doses lead to device degradation. The differences in low versus high doses are highlighted by electron beam induced current and dc characterizations. III-Nitride devices have long been an attractive solution to the ever-increasing high power and speed demands of industry. Of note, AlGaN/GaN high electron mobility transistors (HEMTs) have emerged as a contender for these industrial applications investigated due to their high power and speed capabilities.1 Further, AlGaN/GaN HEMT devices do not require additional doping in contrast to AlGaAs/GaAs. Attention to AlGaN/GaN-based devices for potential space and military applications has incited numerous investigations into device radiation hardness.2 Particularly, the effects of high energy radiations on AlGaN/GaN HEMTs have been investigated, as well as p-i-n diodes for solar blind light detectors.Studies of radiation-induced defects in GaN-based devices have attracted significant interest, and much insight exists into the behavior of III-Nitride-based transistors after exposure to energetic ionizing radiation. Investigations of the radiation effects in AlGaN/GaN-based devices employing energetic protons have consistently reported that proton-irradiation results in a decrease in two-dimensional electron gas (2DEG) sheet carrier concentration and a positive threshold voltage shift with increasing proton dose.2-5 Negative threshold voltage shifts and increase in 2DEG sheet concentration have been observed in AlGaN/GaN HEMT structures exposed to 1-MeV neutron irradiation with doses up to 2.5 × 10 15 cm −2 . 6 In contrast to the behavior observed in proton-irradiated HEMTs, negative threshold voltage shifts are also observed in gamma-irradiated devices. 7-9Even at low altitudes, the fluences of high energy protons, electron, and photons may be non-negligible and depend on many factors including the local solar weather. 10 The interaction of highly energetic particles with matter tend to lead to the generation of secondary gamma radiation. Therefore, it becomes critical to interpret the effects of gamma radiation since it is found in low earth orbits and presents with other high energy radiation-matter interactions. Such investigation is very important not only from fundamental point of view, due to obtaining substantial information on the physical properties of semiconductor materials, but it also gives values of the device performance for application in radiation harsh environments.In recent years, the term gamma-ray has been conventionally de...

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Deep-Level Characterization: Electrical and Optical Methods

Armstrong

Kaplar

2016

Power Electronics and Power Systems

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Direct comparison of traps in InAlN/GaN and AlGaN/GaN high electron mobility transistors using constant drain current deep level transient spectroscopy

Cited by 54 publications

References 25 publications

Review—Ionizing Radiation Damage Effects on GaN Devices

Review—Ionizing Radiation Damage Effects on GaN Devices

Effects of Gamma Irradiation on AlGaN-Based High Electron Mobility Transistors

Deep-Level Characterization: Electrical and Optical Methods

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