Mechanism for Ohmic contact formation of oxidized Ni/Au on <i>p</i>-type GaN

Jang, Ho Won; Kim, Soo Young; Lee, Jong‐Lam

doi:10.1063/1.1586983

Cited by 86 publications

(34 citation statements)

References 28 publications

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“…Several approaches have been implemented to improve the light extraction of GaN-based LEDs, such as employing photonic crystals structures [6], introducing a highly transparent p-contact layer [7], and surface roughening [8]. And among these, the surface roughening is more simple, lowcost and efficient.…”

Section: Introductionmentioning

confidence: 99%

Enhancement of light output powers of GaN-based light emitting diodes with textured indium tin oxide transparent layer by using corrosive liquid

Zhang

et al. 2011

Sci. China Phys. Mech. Astron.

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In order to promote the light output powers of GaN-based light emitting diodes (LEDs), two kinds of novel corrosive liquids have been developed in this paper to roughen the surface of the indium tin oxide (ITO) current spreading layer of LEDs. As a result, the textured transparent ITO layer greatly enhanced the external quantum efficiency of the LEDs. Provided that a wafer sample was dipped in a kind of corrosive liquid developed by us for only about 60 s, the light output powers of the LEDs can be promoted by 24.7%, compared with conventional GaN-based LEDs. It is obvious that the presented method is simple, rapid and cost-effective. GaN-based light emitting diodes (LEDs), corrosive liquid, light output power, textured ITO

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Section: Introductionmentioning

confidence: 99%

Enhancement of light output powers of GaN-based light emitting diodes with textured indium tin oxide transparent layer by using corrosive liquid

Zhang

et al. 2011

Sci. China Phys. Mech. Astron.

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“…2 The ideal metal contact to p-GaN would have a work function greater than that of GaN (;6.5 eV to 7.5 eV). 3,4 For light emitting diodes (LEDs), extraction of the light from the device is paramount to device efficiency and several contact schemes using semitransparent contacts, including oxidized Ni/Au, [5][6][7][8][9][10][11][12] Ru/Ni, 13 Pd/Ni, 14 NiAu, and Al or Ag, 15 indium-tin-oxide-based, 16 and ZnObased, 17 have been reported. The most detailed studies have been reported on the oxidized thin Ni/Au system.…”

Section: Introductionmentioning

confidence: 99%

Calculations and measurements of contact resistance of semi-transparent Ni/Pd contacts to p-GaN

Bogart

Crofton

2006

J. Electron. Mater.

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Calculations of specific contact resistance as a function of doping and barrier height were performed for p-type GaN. These calculations took into account two valence bands, each with different effective masses, and show that at low doping, the heavy hole band accounts for most of the conduction, whereas at heavier doping, the light hole band dominates conduction. These calculations also indicate the barrier height for typical contacts to p-GaN is between 0.75 eV and 1 eV. Specific contact resistance measurements were made for oxidized Ni/Au, Pd, and oxidized Ni/Pd ohmic contact metal schemes to p-GaN. The Ni/Pd contact had the lowest specific contact resistance, 6 3 10 ÿ4 V cm 2 . Auger sputter depth profile analysis showed some Ni diffused away from the GaN surface to the contact surface with the bulk of the Pd located in between two areas of Ni. Both Ni and Pd interdiffused with the GaN at the semiconductor surface. The majority of the oxygen observed was with the Ni as NiO. Angle-resolved-x-ray photoelectron spectroscopy (AR-XPS) analyses showed the formation of predominantly NiO and PdO species, with higher Ni and Pd oxides at the contact surface.

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“…Nevertheless, the Au/Ni/p-GaN [2][3][4][5] structure seems to be the most suitable thanks to relatively good values of the specific contact resistance and optical transparency. By examining the effect of a NiO x layer with a low concentration of oxygen upon the electrical properties of Au/NiO x /p-GaN ohmic contacts [6] it was found that a low-resistance ohmic contact was achieved by Au/NiO x layers deposited by reactive magnetron sputtering and annealed not only in oxygen but also in nitrogen.…”

Section: Introductionmentioning

confidence: 99%

Ohmic Conacts to p-GaN on the Basis of Carbon Nanomaterials

Liday

Vogrinčič

Vretenár

et al. 2015

Journal of Electrical Engineering

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We have designed and verified a new structure for ohmic contacts to p-GaN based on a layer of carbon nanotubes (CNT), reduced graphene oxide (r-GO) and metallic layers of Cr, Pd and Au, namely in configurations Au/Cr/r-GO/CNT/p-GaN and Au/Pd/r-GO/CNT/p-GaN. The effects have been studied of the annealing temperature and the gas ambient upon the electrical properties of the contacts. Annealing of the Au/Pd/r-GO/CNT/p-GaN structure in air at 500 • C for 1 minute resulted in linear I − V curves measured between planar electrodes on the p-GaN. Hence, addition of r-GO to the CNT interlayer between p-GaN and the metallization layer is a highly promising procedure for further improvements of the ohmic contacts to p-GaN.

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Mechanism for Ohmic contact formation of oxidized Ni/Au on p-type GaN

Cited by 86 publications

References 28 publications

Enhancement of light output powers of GaN-based light emitting diodes with textured indium tin oxide transparent layer by using corrosive liquid

Enhancement of light output powers of GaN-based light emitting diodes with textured indium tin oxide transparent layer by using corrosive liquid

Calculations and measurements of contact resistance of semi-transparent Ni/Pd contacts to p-GaN

Ohmic Conacts to p-GaN on the Basis of Carbon Nanomaterials

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