Kinetics and Morphology of GaAs Etching in Aqueous CrO3 ‐ HF Solutions
- 1 April 1986
- journal article
- Published by The Electrochemical Society in Journal of the Electrochemical Society
- Vol. 133 (4) , 799-806
- https://doi.org/10.1149/1.2108680
Abstract
The etching of n‐ and p‐type in aqueous solutions, both under illumination and in the dark, has been studied. On the basis of two ternary composition diagrams, three regions of different etching kinetics can be delineated. These are also regions of different surface morphology after etching. For low ratios and the etching process is kinetically controlled. The etch rate depends on and is independent of . High defect sensitivity is obtained in this part of the ternary diagram. For high ratios and the etching reaction is limited by mass transport of CRVI in solution. Defect sensitivity is poorer in these etchants. For concentrations above 10M, a purely chemical etching reaction becomes important and is dissolved with arsine formation. For all solutions, defects in both p‐ and n‐type crystals are found to dissolve more slowly than the surrounding material. Kinetic and morphological results are explained in detail on the basis of a model for electroless etching.Keywords
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