Electrochemical etching of Si(001) in NH4F solutions: Initial stage and {111} microfacet formation

Shueh Lin Yau, Kazutoshi Kaji, Kingo Itaya

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In situ scanning tunneling microscopy (STM) has been used to examine the etching of an n-Si(001) electrode in 0.1 M NH4F. Cathodic polarization facilitated chemical etching of Si(001) to give {111} microfacets as a result of the tendency of Si to form a monohydride terminated surface. Time-dependent in situ STM atomic images were obtained to demonstrate the preferential etching at the kinks and steps. From the results of the time-dependent imaging, local etching rates were evaluated for the specific crystallographic directions. A Si(001):H-(1×1) square structure was also obtained, demonstrating the presence of dihydride configuration in the beginning of the etching.

Original languageEnglish
Pages (from-to)766
Number of pages1
JournalApplied Physics Letters
StatePublished - 1995


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