Raman study of Mg, Si, O, and N implanted GaN

Katsikini, M.; Papagelis, Konstantinos; Paloura, E. C.; Ves, S.

doi:10.1063/1.1606521

Cited by 99 publications

(62 citation statements)

References 41 publications

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“…The observed shift can be attributed to compressive stress which appears due to the difference in the thermal expansion coefficients of GaN and sapphire. The amount of stress is estimated to Δω/6.2 = 0.74 GPa [13,21]. The peaks at 417.5, 430.0, 449.6, 576.6 and 749.5 cm -1 correspond to A g and E g modes of the Al 2 O 3 substrate [13].…”

Section: Growth Conditions and Experimental Detailsmentioning

confidence: 99%

“…As the fluence increases, the characteristic sharp peaks of the as-grown sample broaden due to relaxation of the q-selection rules allowing phonons with q ≠ 0 to contribute in the Raman scattering. Furthermore, three additional broad peaks are detected in the implanted samples even after implantation with the fluence of 5×10 13 cm -2 . They are ascribed to disorder activated Raman scattering or acoustic overtones (300 cm -1 , 420 cm -1 ) and the formation of point defects (670 cm -1 ), respectively.…”

mentioning

confidence: 94%

“…In the backscattering geometry the E 2 and the A 1 (LO) modes can be detected [10]. The effect of implantation of various ions on the Raman spectra of GaN has been previously reported [11][12][13].…”

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confidence: 99%

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Indium implantation and annealing of GaN: Lattice damage and recovery

Katsikini

Arvanitidis

Ves

et al. 2010

Phys. Status Solidi (c)

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The effect of Indium (In) implantation in n‐type GaN is studied using Raman spectroscopy and Rutherford backscattering (RBS). The RBS analysis reveals that the 700 keV In implantation results in the formation of a subsurface defective region that extends to a depth of 400 nm. An abrupt increase (∼93%) of the maximum defect concentration is observed for fluences in the range 1.5 and 5×1014 cm‐2. A further increase of the fluence to 5×1015 cm‐2 renders the implanted layer amorphous. In the Raman spectra recorded in the backscattering geometry only the E22 peak is resolved since the A1(LO) is completely damped due to plasmon ‐ phonon coupling. As the fluence increases, the characteristic sharp peaks of the as‐grown sample broaden due to relaxation of the q‐selection rules allowing phonons with q ≠ 0 to contribute in the Raman scattering. Furthermore, three additional broad peaks are detected in the implanted samples even after implantation with the fluence of 5×1013 cm‐2. They are ascribed to disorder activated Raman scattering or acoustic overtones (300 cm‐1, 420 cm‐1) and the formation of point defects (670 cm‐1), respectively. Rapid thermal annealing at 1000 °C causes partial recovery of the lattice. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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Section: Growth Conditions and Experimental Detailsmentioning

confidence: 99%

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confidence: 94%

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Indium implantation and annealing of GaN: Lattice damage and recovery

Katsikini

Arvanitidis

Ves

et al. 2010

Phys. Status Solidi (c)

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“…Another peak at 420 cm −1 is attributed to the overtones of transverse acoustic phonons [23,24]. The Raman mode at 300 cm −1 is ascribed to the cation vacancy (Ga vacancy), a host-lattice atom [25,26]. Both PL and Raman spectroscopy confirm the existence of these Ga vacancies in the GaN nanoparticle.…”

Section: Resultsmentioning

confidence: 56%

Ga-vacancy-induced room-temperature ferromagnetic and adjusted-band-gap behaviors in GaN nanoparticles

et al. 2013

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Room-temperature ferromagnetism has been found in Ga-deficient GaN grown using the direct reaction of Ga 2 O 3 powder with NH 3 gas. The observed magnetism in GaN induced by Ga vacancies is investigated both experimentally and theoretically. First-principles calculations reveal that the spontaneous spin polarization is created by the 3.0 μ B local moment for GaN and magnetism originates from the polarization of the unpaired 2 p electrons of N surrounding the Ga vacancy. At the same time, the band gap can be also adjusted by changing the Ga-vacancy concentration.

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“…These extra modes have been attributed to vacancy and vacancy cluster related modes. 22,23 However, after annealing, these peaks are no longer detected and thus the annealing is able to remove most of the implantation damage. It should also be noted that the sapphire substrate is barely detectable in the Raman spectra, indicating that the method is surface sensitive and thus is suitable for characterizing the implanted portion of the GaN.…”

Section: Resultsmentioning

confidence: 99%

Symmetric Multicycle Rapid Thermal Annealing: Enhanced Activation of Implanted Dopants in GaN

Greenlee

Feigelson

Anderson

et al. 2015

ECS J. Solid State Sci. Technol.

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Selectively activated p-type regions are necessary for many electronic devices that require planar processing. The standard process of implanting p-type dopants, such as Mg, in GaN is notoriously more difficult than in other material systems, as the extremely high temperatures required to activate the implanted Mg also damage the GaN surface. In this research, a novel annealing technique is introduced for this purpose -symmetric multicycle rapid thermal annealing (SMRTA). It is shown that SMRTA is superior to the earlier developed multicycle rapid thermal annealing (MRTA) in terms of improvement of the crystalline quality of implanted GaN. The SMRTA technique was applied to Mg-implanted GaN to realize a rectifying junction. The annealing process detailed in this research will be a key enabling step for future GaN-based GaN and other III-nitride based semiconductors have received a great deal of attention from the research community due to favorable material properties which include a tunable direct bandgap, radiation hardness, and a favorable Baliga figure of merit compared to Si and SiC.1,2 The doping of p-type GaN during growth is challenging and has been the focus of numerous studies because it has many potential transformative applications in power electronics and optoelectronics.3 P-type dopant implantation and activation adds additional complexity to the synthesis of p-type GaN. The ability to implant and activate p-type species in GaN is a key enabling process for devices that require selective area doping. Device structures that benefit from the ability to selectively implant and activate p-type dopants in GaN include implanted guard rings for electric field spreading, implanted current blocking layers for current aperture vertical electron transistors, and implanted regions below contacts to lower contact resistance. 4,5 Unfortunately, the implantation and activation of Mg in GaN is difficult because of the high temperatures required (over 1300• C) for the activation anneal, 6 which are significantly higher than the decomposition temperature of GaN at atmospheric pressures (845 • C). 7 The decomposition of GaN occurs due to a loss of nitrogen and results in surface damage and the formation of N vacancies, which are compensating donors. 8To avoid GaN decomposition at the elevated annealing temperatures required for Mg activation, high pressure environments and non-equilibrium annealing conditions combined with capping layers have been investigated. 9,10 GaN can be successfully annealed at about 1500• C, but a 1.5 GPa overpressure of N 2 is necessary to avoid surface degradation.11 Such high gas pressures also require a complicated experimental setup and are not easily industrial scalable. 12A second, more scalable, alternative to the high pressure annealing of GaN relies on using non-equilibrium annealing conditions. For this type of annealing, a capping layer is used to prevent nitrogen loss from the GaN surface. Depending on the material, structure, and thickness of the capping layer, higher annealin...

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Raman study of Mg, Si, O, and N implanted GaN

Cited by 99 publications

References 41 publications

Indium implantation and annealing of GaN: Lattice damage and recovery

Indium implantation and annealing of GaN: Lattice damage and recovery

Ga-vacancy-induced room-temperature ferromagnetic and adjusted-band-gap behaviors in GaN nanoparticles

Symmetric Multicycle Rapid Thermal Annealing: Enhanced Activation of Implanted Dopants in GaN

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