Wet-etching mechanism of a semi-sphere pattern on sapphire substrate

• Published in: Materials chemistry and physics Vol. 281; p. 125863
• Main Authors: Liu, C.Y., Yeh, C.Y., Lai, W.H., Chou, C.Y., Li, X.F., Cheng, C., Huang, C.K., Lai, T.L.
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 01.04.2022; Elsevier BV
• Subjects: Aluminum phosphate; Aluminum sulfate; Apexes; Etchants; Etching; Light emitting diodes; Patterned sapphire substrate; Phosphoric acid; Radicals; Sapphire; Screening; Substrates; Sulfuric acid; Triangles; Wet etching; Wet etching; Light emitting diodes; Patterned sapphire substrate

A semi-spherical pattern can be converted to a triangular pyramid comprising three r-planes using chemical wet etching with a mixture of sulfuric and phosphoric acids. The apex Al atom on the triangular pyramid with numerous dangling bonds can be subject to etching with prolonged exposure. After rem...