Temperature dependence of the E2 and A1(LO) phonons in GaN and AlN

Link, A.; Bitzer, Karl; Limmer, W.; Sauer, R.; Kirchner, C.; Schwegler, V.; Kamp, M.; Ebling, D.

doi:10.1063/1.371681

Cited by 122 publications

(99 citation statements)

References 15 publications

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“…Similar deep depletion features with no inversion characteristics were reported in SiO 2 /GaN ͑Ref. 22͒ and SiO 2 /SiC systems, 33 because the generation rate of the minority carriers ͑holes in this case͒ is extremely low at room temperature in wide-gap semiconductor MIS systems. These results indicated that the SiN x -gate control of surface potential was achieved over a remarkably wide within the bandgap of GaN.…”

Section: B Surface Passivation Of Gan and Ganõalgan Surfaces By Sio supporting

confidence: 78%

Surface passivation of GaN and GaN/AlGaN heterostructures by dielectric films and its application to insulated-gate heterostructure transistors

Hashizume

Ootomo

Inagaki

et al. 2003

Journal of Vacuum Science &Amp; Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena

220

170

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We have systematically investigated effects of plasma processing, formation of Si-based dielectrics, and formation of a thin Al 2 O 3 film on the chemical and electronic properties of GaN and GaN/ AlGaN heterostructure surfaces. The surface treatment in H 2 -plasma excited by electron-cyclotron-resonance ͑ECR͒ source, produced nitrogen-vacancy-related defect levels at GaN and AlGaN surfaces, while the ECR-N 2 -plasma treatment improved electronic properties of the surfaces. The deposition of a SiO 2 film on GaN and AlGaN surfaces was found to induce high-density interface states, due to unexpected and uncontrollable oxidation reactions on the surfaces during the deposition process. In comparison, the SiN x /GaN passivation structure prepared by ECR-plasma assisted chemical vapor deposition showed good interface properties with the minimum D it value of 1ϫ10 11 cm Ϫ2 eV Ϫ1 . However, excess leakage currents governed by FowlerNordheim tunneling were observed in the SiN x /Al 0.3 Ga 0.7 N structure, due to a relatively small conduction band offset of 0.7 eV between SiN x and Al 0.3 Ga 0.7 N. A novel Al 2 O 3 -based passivation structure was proposed and fabricated by molecular beam deposition of Al and subsequent ECR O 2 -plasma oxidation. In situ x-ray photoelectron spectroscopy showed successful formation of the Al 2 O 3 layer with a thickness of 3.5 nm and a large conduction band offset of 2.1 eV between Al 2 O 3 and A 0.3 Ga 0.7 N. The GaN/AlGaN insulated-gate heterostructure field-effect transistors ͑IG HFETs͒ having the Al 2 O 3 -based passivation structure showed a good gate control of drain currents up to V GS ϭϩ3 V and achieved drain saturation current of 0.8 A/mm. The observed maximum g m value is 120 mS/mm. No current collapse was observed in the Al 2 O 3 IG HFETs, indicating a remarkable advantage of the present Al 2 O 3 -based passivation structure.

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Section: B Surface Passivation Of Gan and Ganõalgan Surfaces By Sio supporting

confidence: 78%

Surface passivation of GaN and GaN/AlGaN heterostructures by dielectric films and its application to insulated-gate heterostructure transistors

Hashizume

Ootomo

Inagaki

et al. 2003

Journal of Vacuum Science &Amp; Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena

220

170

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“…Phonon lifetimes and decay channels can be studied by means of temperature-dependent Raman-scattering experiments [10]. Raman-scattering studies of the decay of zone-center phonons have been carried out on several wurtzitetype semiconductors [11][12][13] and, more specifically, studies of wurtzite-type GaN have been extensively reported [14][15][16][17][18]. The analysis of the temperature dependence of the phonon linewidths is generally carried out by fitting a simplified theory of anharmonic decay in which, to the lowest order, the frequency shift and the broadening of the phonon line shapes is proportional to the sum of Bose-Einstein factors associated with the phonon decay products.…”

Section: Introductionmentioning

confidence: 99%

Anharmonic phonon decay in cubic GaN

et al. 2015

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We present a Raman-scattering study of optical phonons in zinc-blende (cubic) GaN for temperatures ranging from 80 to 750 K. The experiments were performed on high-quality, cubic GaN films grown by molecular-beam epitaxy on GaAs (001) substrates. The observed temperature dependence of the optical phonon frequencies and linewidths is analyzed in the framework of anharmonic decay theory, and possible decay channels are discussed in the light of density-functional-theory calculations. The longitudinal-optical (LO) mode relaxation is found to occur via asymmetric decay into acoustic phonons, with an appreciable contribution of higher-order processes. The transverse-optical mode linewidth shows a weak temperature dependence and its frequency downshift is primarily determined by the lattice thermal expansion. The LO phonon lifetime is derived from the observed Raman linewidth and an excellent agreement with previous theoretical predictions is found.

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“…14 The obtained temperature and Al content dependence of Raman shift and linewidth can be used for deriving calibration curves as reported in MgZnO layer. 25 The local temperature for the (AlGa) 2 O 3 -based devices in operation can thus be determined by the calibration curve. 14 Moreover, the information of the anharmonic effect is also important for the (AlGa) 2 O 3 -based device applications, because the degree of lattice disorder in mirrors by Raman microprobe spectroscopy correlates to the strength of facet heating and to the power limit at optical mirror damage.…”

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confidence: 99%

Temperature dependence of Raman scattering in β-(AlGa)2O3 thin films

et al. 2016

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We report a detailed investigation on temperature-dependent Raman scattering of β-(AlGa)2O3 thin films with different Al content (0-0.72) under the temperature range of 77-300 K. The temperature-dependent Raman shifts and linewidths of the phonon modes were obtained by employing Lorentz fitting. The linewidths broadening of phonon modes with the temperature can be well explained by a model involving the effects of thermal expansion, lattice-mismatch-induced strain, and decay of optical phonon into two and three phonons. It is clearly demonstrated dependence of the linewidths and decay process on the Al content in β-(AlGa)2O3 thin films, which can provide an experimental basis for realization of (AlGa)2O3-based optoelectronic device applications.

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Temperature dependence of the E2 and A1(LO) phonons in GaN and AlN

Cited by 122 publications

References 15 publications

Surface passivation of GaN and GaN/AlGaN heterostructures by dielectric films and its application to insulated-gate heterostructure transistors

Surface passivation of GaN and GaN/AlGaN heterostructures by dielectric films and its application to insulated-gate heterostructure transistors

Anharmonic phonon decay in cubic GaN

Temperature dependence of Raman scattering in β-(AlGa)2O3 thin films

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