UBC Theses and Dissertations
Modeling surface pattern evolution during thermal Cl₂ etching of GaAs (001) Mar, Richard Elliot
The morphology of GaAs (001) single crystals during thermal chlorine etching was studied in this work. Models that can predict the evolution of 3 fxm pitch, 100 nm amplitude wet etched gratings were developed. A model was developed in which the etch rate and the angle of the exposed crystal plane with respect to the (001) plane were associated. Additional effects such as the formation of chlorine adatoms and surface diffusion were included to provide better agreement with the experimental data. The possibility of chlorine sliding along the surface due to the initial momentum from the incident beam was also considered. By comparing experimental cross sections obtained by atomic force microscopy with simulations, we found that the chlorine diffusion length was approximately 50 nm. Better agreement with the experimental data was observed when using an average sliding distance of approximately 11 nm.
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