To establish the self-limiting reaction process that is necessary to achieve the atomic layer-by-layer etching for the damageless fabrication of nanometer-electronics devices, the initial reaction of fluorine (F) atoms and molecules with hydrogen (H)-terminated Si(111) was studied employing a combined system of Fourier transform infrared (FTIR)-attenuated total reflection (ATR) and x-ray photoelectron spectroscopy (XPS). In the ATR measurement, peaks of and newly appeared instead of a decrease in the original Si–H peak at with initial exposure of The sum area of , , and peaks until was almost constant. This implies that and peaks also resulted from Si–H bonds. The XPS measurement revealed that the initial exposure of generated nonbonded F atoms at first, followed by bonds. Based on the good correspondence between ATR and XPS results, first the F atoms penetrate just underneath the Si–H bond, generating the peak. After further exposure the peak appears arising from the bonding of an F atom with a Si–H bond at the five-coordination state. However, further exposure of F atoms caused higher order products. Hence, an gas that was less reactive than F atoms was investigated. It was found that the exposure of H-terminated Si(111) to 5% reached a plateau value at where terminated H atoms completely disappeared. The SiF monolayer corresponded exactly to the formation of an atomic layer of Si(111). This indicates that the self-limiting process for the Si/F system is realized first.
Reaction of the fluorine atom and molecule with the hydrogen-terminated Si(111) surface
Yasuhiro Morikawa, Kazuhiro Kubota, Hiroki Ogawa, Takanori Ichiki, Akitomo Tachibana, Shuzo Fujimura, Yasuhiro Horiike; Reaction of the fluorine atom and molecule with the hydrogen-terminated Si(111) surface. J. Vac. Sci. Technol. A 1 January 1998; 16 (1): 345–355. https://doi.org/10.1116/1.581004
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