Influence of oxygen on the activation of <i>p</i>-type GaN

Hull, B. A.; Mohney, Suzanne E.; Venugopalan, H. S.; Ramer, J.

doi:10.1063/1.126318

Cited by 90 publications

(58 citation statements)

References 6 publications

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“…Recently, many reports have shown that annealing in N 2 /O 2 gas mixtures [10][11][12] or in air [13] increased hole concentrations significantly even at low temperatures (<600 °C). These results suggest that oxygen plays an important role in breaking the Mg-H complex at relatively low temperatures, however the role of oxygen in this process is not yet understood.…”

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confidence: 99%

Influence of oxygen on luminescence and vibrational spectra of Mg‐doped GaN

Koide

Walker

White

et al. 2003

Physica Status Solidi (b)

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Mg-doped GaN epilayers are analyzed by Raman and low-energy electron-excited nanoluminescence (LEEN) spectroscopies before and after oxygen ambient annealing at temperatures from 450 to 550 °C. Annealing as low as 450 °C shows the appearance of a local vibrational mode of the Mg Ga acceptor. Correspondingly, LEEN emission at 2.8 eV increases and that at 3.27 eV decreases after annealing in oxygen ambient. On the other hand, electron beam treatment decreases 2.8 eV emission and increases 3.27 eV emission. These luminescence properties are explained by a donor-acceptor pairs transition model due to hydrogen-related deep and shallow donors and Mg Ga acceptor.

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mentioning

confidence: 99%

Influence of oxygen on luminescence and vibrational spectra of Mg‐doped GaN

Koide

Walker

White

et al. 2003

Physica Status Solidi (b)

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“…The structures differ in the stacking order of the close packed diatomic planes [ Figure 2.1]. The wurtzite structure has a stacking order of AaBbAa… along the [0001] while the zincblende structure has a stacking order of AaBbCcAa… along the [111]. A, B, C (a, b, c) denote the cation (anion) atoms.…”

Section: Crystal Structurementioning

confidence: 99%

“…H is always present in MOCVD growth as it is used as the H 2 carrier gas and in the precursors (TMA, TMG, NH 3 ). Annealing in N 2 or O 2 ambient was found to be an effective method to reduce the H by out-diffusion and to activate the Mg acceptors and achieve p-type conductive GaN and AlN [97,111].…”

Section: Mg Doping Of Alganmentioning

confidence: 99%

Doping of high-Al-content AlGaN grown by MOCVD

Nilsson¹

2014

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The high-Al-content Al x Ga 1-x N, x > 0.70, is the principal wide-band-gap alloy system to enable the development of light-emitting diodes operating at the short wavelengths in the deep-ultraviolet, λ < 280 nm. The development of the deep-ultraviolet light-emitting diodes (DUV LEDs) is driven by the social and market impact expected from their implementation in portable units for water/surface disinfection and based on the damaging effect of the deep-ultraviolet radiation on the DNA of various microorganisms. Internationally, intense research and technology developments occur in the past few years, yet, the external quantum efficiency of the DUV LEDs is typically below 1%.One of the main material issues in the development of the DUV LEDs is the achievement of n-and ptype high-Al-content Al x Ga 1-x N layers with low resistivity, which is required for the electrical pumping of the diodes. The doping process becomes significantly more complex with increasing the Al content and the electrical resistivity is as high as 10 1 -10 2 Ω . cm for n-type AlN doped by silicon, and 10 7 -10 8 Ω cm for p-type AlN doped by magnesium.The present study was therefore focused on gaining a better understanding of the constraints in the doping process of the high-Al-content Al x Ga 1-x N alloys, involving mainly silicon. For this purpose, the epitaxial growth of the high-Al-content Al x Ga 1-x N and AlN by implementing the distinct hot-wall MOCVD was developed in order to achieve layers of good structural and morphological properties, and with low content of residual impurities, particularly oxygen and carbon. Substitutional point defects O N and C N may have a profound impact on the doping by their involvement in effects of ntype carrier compensation. The process temperature was varied between 1000 and up to 1400 °C, which is a principal advantage in order to optimize the material properties of the high-Al-content Al x Ga 1-x N and AlN. The epitaxial growth of the high-Al-content Al x Ga 1-x N and AlN was largely performed on 4H-SiC substrates motivated by (i) the lattice mismatch of ~ 1% along the basal plane (the smallest among other available substrates including Si and sapphire), (ii) the good thermal conductivity of 3.7 W cm -1 K -1 , which is essential to minimize the self-heating during the operation of any light-emitting diode, and (iii) the limited access to true-bulk AlN wafers. The outcome of this study is accordingly summarized and presents our understanding for (i) the complex impact of silicon and oxygen on the n-type conductivity of Al 0.77 Ga 0.23 N, representative for the alloy composition at which a drastic reduction of the n-type conductivity of Al x Ga 1-x N is commonly reported (paper 1); (ii) the strain and morphology compliance during the intentional iv doping by silicon and magnesium, and its correlation with the resistivity of highly doped layers of Al 0.82 Ga 0.18 N alloy composition (paper2); (iii) the n-type conductivity of highly Si-doped Al 0.72 Ga 0.28 N as bound by the process temperature (p...

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“…Waki et al reported that a thin Ni metal is permeable and absorbs hydrogen liberated from pGaN [3]; consequently deposition of a Ni layer might enhance the removal of hydrogen from p-GaN. Hull et al showed further that annealing p-GaN with a metal layer in an environment of O 2 facilitated removal of residual hydrogen via formation and desorption of H 2 O [6]. On the basis of previous work, an efficient method of extracting hydrogen from p-GaN was proposed to be performed without thermal damage.…”

Section: Introductionmentioning

confidence: 96%

Bias‐assisted activation of p‐GaN at low temperature in air

Hwang

Hung

Hwang

2004

phys. stat. sol. (c)

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For the bias-assisted activation of p-GaN at low temperature in air, we deposited various metal contacts consisting of thin Ni/Au and Ni/Pt, and thick Ni layer structures. Annealing these metal contacts with an electrical bias enhances the diffusion of residual hydrogen in the p-GaN towards the interface. The hydrogen was enhanced accumulated at the interface between metal and p-GaN by bias applied. The extracted hydrogen can diffuse through the thin Ni/Au and Ni/Pt metal contacts and desorb from the surface under bias-assisted activation at 410 °C in air. The total resistance of the metal contact to p-GaN after biasassisted activation decreases without thermal damage. In contrast, for a thick Ni contact on p-GaN, hydrogen accumulated at the interface, and diffusion of hydrogen into the air was obstructed. This condition results in a deteriorated contact resistance and decreases the transport current of the metal contact to p-GaN. The bias-assisted activation with thin Ni/Pt or Ni/Au contacts at 410 °C is practical to remove residual hydrogen from p-GaN and subsequently decreases the contact resistance.

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Influence of oxygen on the activation of p-type GaN

Cited by 90 publications

References 6 publications

Influence of oxygen on luminescence and vibrational spectra of Mg‐doped GaN

Influence of oxygen on luminescence and vibrational spectra of Mg‐doped GaN

Doping of high-Al-content AlGaN grown by MOCVD

Bias‐assisted activation of p‐GaN at low temperature in air

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