Atomic scale etching processes ofn‐Si(111) in NH4F solutions:In situscanning tunneling microscopy
作者:
Kazutoshi Kaji,
Shueh‐Lin Yau,
Kingo Itaya,
期刊:
Journal of Applied Physics
(AIP Available online 1995)
卷期:
Volume 78,
issue 9
页码: 5727-5733
ISSN:0021-8979
年代: 1995
DOI:10.1063/1.359633
出版商: AIP
数据来源: AIP
摘要:
Insituscanning tunneling microscopy (STM) was employed to examine the electrochemical etching process of ann‐Si(111) electrode in dilute NH4F solutions under potential control. Time‐dependent STM images have revealed prominent effects of microscopic structures of Si on the rate of its dissolution. Multiple hydrogen‐terminated Si atoms at the kink and step sites were eroded more rapidly than the monohydride Si step. This presumably resulted from the difference in reactivity of these hydrogen‐terminated Si species. It is demonstrated that the density of kinks plays a main role in controlling the etching rate of Si. In the absence of kinks, not only the monohydride but also the dihydride steps were found to be stable. The etching rate of the monohydride step is substantially increased from a negligible value to 15 nm/min by the introduction of kink sites. The average etching rate for a dihydride step was 32 nm/min. Overall, the difference in the reactivity guides the dissolution of Si in a layer‐by‐layer fashion. ©1995 American Institute of Physics.
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