Delayed <111> texture for improving the thermal stability of Ag reflectors for high-performance GaN-based light-emitting diodes

Low-damage sputtered silver ohmic contacts to p-GaN with thermal stability

“…The reflectivity of the sputtered Ag films was slightly reduced to 94%, whereas that of the e-beam Ag films was reduced significantly to 72% after annealing at 673 K. The inset shows variation in surface morphology of both the Ag films. The sputtered Ag films showed a smooth surface, whereas the e-beam Ag films yielded an agglomerated surface morphology after annealing at 673 K, which can be attributed to the poor adhesion of the e-beam Ag followed by formation of voids at the Ag/p-GaN interface [7]. Note that ρ c of both the sputtered and e-beam Ag film was reduced by one order of magnitude after annealing at 673 K [8].…”

Improved Light Output Power of Ultraviolet GaN-Based Light-Emitting Diode by Using AgPdCu Reflector

“…However, the APC sample that was less (111)-oriented did not undergo agglomeration. It is envisaged from these results that the thermal stability of Ag-based films can be improved by hindering (111) texturing [24,25]. This means that for the APC sample, the presence of Pd and Cu atoms hampered the evolution of (111) texturing.…”

Electrical Characteristics of Thermally Stable Ag–Pd–Cu Alloy Schottky Contacts on n-Al0.6Ga0.4N

“…This result is consistent with the finding that Pd and Cu atoms delayed the conversion of 〈100〉-textured grains into 〈111〉-textured ones, which are beneficial for increasing agglomeration resistance. 54 The XRD results (Fig S3, Supplementary Information) showed that for the APC samples, the magnitude of the Ag (111) peak increased only marginally with temperature. According to the Ag-Pd and Ag-Cu binary phase diagrams, 55,56 the Ag-Cu alloy was either an eutectic alloy or a solid solution below 700 °C, whereas the Ag-Pd alloy was a solid solution.…”

“…27,[57][58][59] In other words, the presence of Cu and Pd atoms may have delayed the conversion of Ag 〈100〉textured grains into 〈111〉-textured ones, thus enhancing the thermal stability. 54 Figure 8 displays TEM images of the APC/n-AlGaN interface regions before and after heat-treatment at 300 °C. The as-deposited sample contained micro-voids at the APC-n-AlGaN interface, whereas the 300 °C-annealed APC sample contained no voids.…”