Low resistance and transparent Ni–La solid solution/Au ohmic contacts to <i>p</i>-type GaN

Song, June O.; Leem, Dong‐Seok; Kwak, Joon Seop; Lee, S. N.; Nam, Okhyun; Park, Y.; Seong, Tae Yeon

doi:10.1063/1.1652238

Cited by 13 publications

(5 citation statements)

References 22 publications

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“…Song et al also obtained a transparency of 74% at 470 nm with their Zn‐Ni ss/Au contact, a transparency of 82.5% at 470 nm with the Ni‐La ss/Au contact, and 79% at 460 nm with the Ni‐Mg ss/Au contact …”

Section: High Transparency Materialsmentioning

confidence: 94%

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Ohmic Contacts on p‐GaN

Chen

Brewer

2015

Adv Elect Materials

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With the development of GaN-based optoelectronic devices, the need for p-GaN contacts with low resistivity, good thermal stability, and high transparency or refl ectivity has become more pressing. Various contact schemes to satisfy these requirements have been investigated in the past two decades. In this progress report, the main developments of contacts on p-GaN throughout these years are summarized. The primary focus is on the materials aspects of the contacts and the functional mechanisms related to their relevant properties.

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Section: High Transparency Materialsmentioning

confidence: 94%

“…Metals which readily absorb H were also used for p‐GaN contact metal schemes, such as La in a Ni‐La ss contact by Song et al and Cr in Cr/Au contacts in the work of Kalaitzakis et al…”

Section: Metal Contactsmentioning

confidence: 99%

Ohmic Contacts on p‐GaN

Chen

Brewer

2015

Adv Elect Materials

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“…A specific contact resistance of around approximately 10 À2 -10 À6 cm 2 can be achieved in the Ni/Au, 1,2) Ni/Pt/Au, 3) Ni/Pd/Au, 4) Ni/ AuBe, 5) Ni/ZnO, 6) and Ni-Mg (La or Zn) solid solution/Au series. [7][8][9] Many studies concerning Ni have been carried out. Thus, it is important to understand the interfacial reactions between Ni and GaN.…”

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confidence: 99%

Thermal Annealing Effect Between Ni Film and Mg-Doped GaN Layer

Hsu

Lan

2006

jjap

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The effects of thermal annealing between Ni film and a p-type GaN layer have been investigated. The electrical and optical properties were measured by Hall effect, capacitance–voltage (C–V) and photoluminescence (PL) measurements. The samples activated with Ni film obtained higher effective carrier concentrations than those activated without Ni film. Effective carrier concentrations of 5×1015 and 1×1017 cm-3 were achieved at an activating temperature of 400 °C without and with Ni film. The Ni film may act as a catalyst for the activation of Mg-doped GaN at a temperature less than 500 °C. At a temperature higher than 600 °C, the Ni film may react with the Mg-doped GaN. X-ray diffraction (XRD) analyses indicated that Ni film on Mg-doped GaN transforms to nickel oxide (NiO) and nickel nitride (Ni3N) during thermal annealing in air. The peaks of the PL spectra at 15 K of the samples activated at 600 °C with and without Ni film were observed at approximately 3.2 and 2.9 eV. We suggest that Ni atoms not only enhance hydrogen desorption but also diffuse into the Mg-doped GaN layers to form Ni-compound materials. At a high annealing temperature, impurities such as Ni nitride, nitrogen vacancies or other defects may reduce the carrier mobility and provide an increase in the effective carrier concentrations in the surface region.

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“…The surface morphology can become very rough, especially in the case of the common Ni/Au contact, and the contact can fail to display Ohmic properties. A number of approaches to compensate for this problem have been explored, including the use of non-alloyed Rh-based contacts [22] and Pd [23], W [29], as well as families of borides [30,31] and nitrides [32].…”

Section: Introductionmentioning

confidence: 99%