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ACS Appl Mater Interfaces
; 6(10): 7028-31, 2014 May 28.
Article
in English
| MEDLINE
| ID: mdl-24818868
ABSTRACT
We describe pH-controlled selective etching of atomic layer deposition (ALD) Al2O3 over ZnO. Film thickness as a function of etch exposure was measured by spectroscopic ellipsometry. We find that alkaline aqueous solutions with pH between about 9 and 12 will etch Al2O3 at useful rate with minimal attack of ZnO. Highly selective etching of Al2O3 over ZnO (selectivity >400:1) and an Al2O3 etch rate of â¼50 nm/min can be obtained using a pH 12 etch solution at 60 °C.