Role of Ag-alloy in the thermal stability of Ag-based ohmic contact to GaN(0 0 0 1) surface

Xiong, Zhihua; Qin, Zhenzhen; Zhao, Qian; Chen, Lanli

doi:10.1016/j.scriptamat.2014.11.034

Cited by 7 publications

(3 citation statements)

References 31 publications

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“…Alloying is a simple and effective method for improving the performance of pure metals [6,7]. Among the numerous available alloys [8][9][10], Ag-Cu alloys [11,12] are a commonly used silver alloy for electrical contacts and decoration purposes, due to its improved mechanical performance, good electrical and thermal conductivity, and moderate cost. However, the introduction of the Cu element reduces the Ag's chemical stability, such that the Ag-Cu alloy is more likely to react with the element sulfur to generate black sulfides, in comparison to pure silver [13].…”

Section: Introductionmentioning

confidence: 99%

Microstructure, Mechanical Properties, and Corrosion Resistance of Ag–Cu Alloys with La2O3 Fabricated by Selective Laser Melting

Zhao,

Zheng,

et al. 2023

Materials

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Ag and its alloys, when prepared by a selective laser melting (SLM) process, have a low density and poor overall performance due to their high reflectivity when the most commonly used laser (λ = 1060 nm) is used, and they have exorbitant thermal conductivity. These characteristics lead to the insufficient melting of the powders and severely limit the applications of additive manufactured silver alloys. To improve the absorption of the laser, as well as for better mechanical properties and higher resistance to sulfidation, Ag–Cu alloys with different La2O3 contents were prepared in this work using the SLM process, via the mechanical mixing of La2O3 nanoparticles with Ag–Cu alloy powders. A series of analyses and tests were conducted to study the effects of La2O3 in Ag–Cu alloys on their density, microstructure, mechanical properties, and corrosion resistance. The results revealed that the addition of La2O3 particles to Ag–Cu alloy powders improved the laser absorptivity and reduced defects during the SLM process, leading to a significant rise from 7.76 g/cm3 to 9.16 g/cm3 in the density of the Ag–Cu alloys. The phase composition of the Ag–Cu alloys prepared by SLM was Silver-3C. La2O3 addition had no influence on the phase composition, but refined the grains of the Ag–Cu alloys by inhibiting the growth of columnar grains during the SLM process. No remarkable preferred orientation existed in all the samples prepared with or without La2O3. An upwards trend was achieved in the hardness of the Ag–Cu alloy by increasing the contents of La2O3 from 0 to 1.2%, and the average hardness was enhanced significantly, from 0.97 GPa to 2.88 GPa when the alloy contained 1.2% La2O3 due to the reduced pore defects and the refined grains resulting from the effects of the La2O3. EIS and PD tests of the samples in 1% Na2S solution proved that La2O3 addition improved the corrosion resistance of the Ag–Cu alloys practically and efficaciously. The samples containing La2O3 exhibited higher impedance values and lower corrosion current densities.

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Section: Introductionmentioning

confidence: 99%

Microstructure, Mechanical Properties, and Corrosion Resistance of Ag–Cu Alloys with La2O3 Fabricated by Selective Laser Melting

Zhao,

Zheng,

et al. 2023

Materials

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“…The agglomeration usually causes a light scattering phenomenon and decreased conductivity with respect to the initial smooth layer, thus decreasing the specular reflection and conductivity [6][7][8][9][10]. In the past decade, thermal stability or thermal degradation (i.e., agglomeration) of Ag films on GaN-related semiconductors for LEDs have been extensively investigated in many studies [11][12][13][14][15][16][17][18][19][20]. One solution for improving the thermal stability of Ag films was proposed by adopting capping layers like NiZn alloy [11], SnO 2 [12], Zn [13], and IZO [15] on Ag films, or using interlayers like Ni [14] and Ir [15] layers beneath the Ag films, to retard the Ag agglomeration process at high temperature.…”

Section: Introductionmentioning

confidence: 99%

“…La [17], Ni [18], Zn or Sn [19,20] into Ag films to hinder the migration of Ag grains at high temperature. Moreover, Ag reacts readily with sulfur around and forms a silver sulfide film on the surface during assembling process and application circumstance, thus lowering their reflective performance and luminous efficiency of LED packages.…”

Section: Introductionmentioning

confidence: 99%

Thermal Stability and Sulfidizing Resistance of High Reflective Multilayered Sn/Ag3Sn and Sn/Ag Films Electrodeposited on Cu Alloy Sheets

Kure‐Chu

Ogasawara

et al. 2016

Electrochimica Acta

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We reported multilayered Sn/Ag 3 Sn and Sn/Ag films with Ag thickness of 20-300 nm that electroplated on a reflowed Sn layer on Cu alloy sheets as promising coating materials for LED lead-frames. The morphology, surface roughness, crystalline structure, and reflectance of multilayered Sn/Ag-based films are more dependent on plating baths than on Ag thickness. The Sn/Ag 3 Sn film obtained from a cyanide Ag bath exhibited high specular reflectivity of 65-70% (480 nm), whereas the Sn/Ag films from a cyanide-free bath showed a high total reflectivity of 94% similar to commercial Ag films. The reflectance of both the multilayered Sn/Ag 3 Sn and Sn/Ag films almost unchanged even after heating at 373 K for 120 h, in comparison with the apparent drop for a commercial Ag film. Moreover, the multilayered Sn/Ag 3 Sn films, both the as-deposited and the annealed specimens, remained the reflectivity even after immersing in a

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Insight into the Al/N-GaN barrier property to realize high quality n-type Ohmic contact

Wang

Xiong

Zhao

et al. 2020

Journal of Alloys and Compounds

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Role of Ag-alloy in the thermal stability of Ag-based ohmic contact to GaN(0 0 0 1) surface

Cited by 7 publications

References 31 publications

Microstructure, Mechanical Properties, and Corrosion Resistance of Ag–Cu Alloys with La2O3 Fabricated by Selective Laser Melting

Microstructure, Mechanical Properties, and Corrosion Resistance of Ag–Cu Alloys with La2O3 Fabricated by Selective Laser Melting

Thermal Stability and Sulfidizing Resistance of High Reflective Multilayered Sn/Ag3Sn and Sn/Ag Films Electrodeposited on Cu Alloy Sheets

Insight into the Al/N-GaN barrier property to realize high quality n-type Ohmic contact

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