Impact of proton irradiation on deep level states in n-GaN

Zhang, Z.; Arehart, Aaron R.; Cinkilic, Emre; Chen, J.; Zhang, E. X.; Fleetwood, D.M.; Schrimpf, R.D.; McSkimming, Brian M.; Speck, J. S.; Ringel, S. A.

doi:10.1063/1.4816423

Cited by 67 publications

(28 citation statements)

References 31 publications

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“…The Arrhenius data of both the E C -0.57 and E C -0.72 eV trap show excellent agreement (see Fig. 6) with that collected from bulk GaN materials studies in the past [13]. This overlap suggests that both these levels are located within the GaN buffer.…”

Section: Resultssupporting

confidence: 64%

Identification of an RF degradation mechanism in GaN based HEMTs triggered by midgap traps

Sasikumar

Arehart

Via

et al. 2015

Microelectronics Reliability

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Quantitative defect spectroscopy was performed on low gate leakage operational S-band GaN HEMTs before and after RF accelerated life testing (ALT) to investigate and quantify potential connections between the evolution of observed traps and RF output power loss in these HEMTs after stressing. Constant drain current deep level transient spectroscopy and deep level optical spectroscopy (CI D -DLTS and CI D -DLOS, respectively) were used to interrogate thermally-emitting traps (CI D -DLTS) and deeper optically-stimulated traps (CI D -DLOS) so that the entire bandgap can be probed systematically before and after ALT. Using drain-controlled CI D -DLTS/DLOS, with which traps in the drain access region are resolved, it is found that an increase in the concentration of a broad range of deep states between E C -1.6 to 3.0 eV, detected by CI D -DLOS, causes a persistent increase in on-resistance of 0.22 Ω-mm, which is a likely source for the 1.2 dB reduction in RF output power that was observed after stressing. In contrast, the combined effect of the upper bandgap states at E C -0.57 and E C -0.72 eV, observed by CI D -DLTS, is responsible for only~10% of the on-resistance increase. These results demonstrate the importance of discriminating between traps throughout the entire bandgap with regard to the relative roles of individual traps on degradation of GaN HEMTs after ALT.

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Section: Resultssupporting

confidence: 64%

Identification of an RF degradation mechanism in GaN based HEMTs triggered by midgap traps

Sasikumar

Arehart

Via

et al. 2015

Microelectronics Reliability

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“…[229]. It should be mentioned, however, that, in proton irradiated n-GaN grown by NH 3 -MBE, the observed carrier removal was attributed to compensation by ET15 C interstitials and to C-related shallow acceptors in the lower half of the bandgap (those will be discussed in a moment, see also the C doping effects section above) [219]. However, it needs to be understood in more detail how this can be the case.…”

Section: Deep Traps In Ganmentioning

confidence: 96%

Deep traps in GaN-based structures as affecting the performance of GaN devices

Polyakov

Lee

2015

Materials Science and Engineering: R: Reports

205

177

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“…5,12,16,[21][22][23][24][25][27][28][29][30][31][32][33][34][35][36][37][42][43][44][45][46][47][49][50][51][52][53][54][55][56][57][58]79 For the high energy protons encountered in space-based applications, AlGaN/GaN HEMTs show decreases in tranconductance (g m ), drain-source current (I DS ), shifts in threshold voltage (V T ) and gate current (I G ) after irradiation with 40 MeV protons at doses equivalent to decades in low-earth orbit. These protons create deep electron traps that increase the HEMT channel resistance and decrease carrier mobility.…”

Section: Changes In Gan-based Hemt Performance After Irradiationmentioning

confidence: 99%

“…There are still a number of issues where additional work is needed, 2,12,56,57,79,[200][201][202][203][204][205][206][207][208] including:…”

mentioning

confidence: 99%

Review—Ionizing Radiation Damage Effects on GaN Devices

Pearton

Ren

Patrick

et al. 2015

ECS J. Solid State Sci. Technol.

267

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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Impact of proton irradiation on deep level states in n-GaN

Cited by 67 publications

References 31 publications

Identification of an RF degradation mechanism in GaN based HEMTs triggered by midgap traps

Identification of an RF degradation mechanism in GaN based HEMTs triggered by midgap traps

Deep traps in GaN-based structures as affecting the performance of GaN devices

Review—Ionizing Radiation Damage Effects on GaN Devices

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