KOH based selective wet chemical etching of AlN, AlxGa1-xN, and GaN crystals: A way towards substrate removal in deep ultraviolet-light emitting diode

Journal Article · Mon Feb 23 00:00:00 EST 2015 · Applied Physics Letters

DOI:https://doi.org/10.1063/1.4913705· OSTI ID:1211346

Guo, W; Kirste, R; Bryan, I; Bryan, Z; Hussey, L; Reddy, P; Tweedie, J; Collazo, R; Sitar, Z

A controllable and smooth potassium hydroxide-based wet etching technique was developed for the AlGaN system. High selectivity between AlN and AlxGa1-xN (up to 12 x) was found to be critical in achieving effective substrate thinning or removal for AlGaN-based deep ultraviolet light emitting diodes, thus increasing light extraction efficiency. The mechanism of high selectivity of AlGaN as a function of Al composition can be explained as related to the formation and dissolution of oxide/hydroxide on top of N-polar surface. Cross-sectional transmission electron microscopic analysis served as ultimate proof that these hillocks were not related to underlying threading dislocations. (C) 2015 AIP Publishing LLC.

• Sponsoring Organization: USDOE Advanced Research Projects Agency - Energy (ARPA-E)
• DOE Contract Number: DE-AR0000299
• OSTI ID: 1211346
• Journal Information: Applied Physics Letters, Vol. 106, Issue 8; ISSN 0003-6951
• Country of Publication: United States
• Language: English