Chemistry of 1,1,1,5,5,5-hexafluoro-2,4-pentanedione on Si(100)-2×1

MÉNDEZ DE LEO, LUCILA P.; PIROLLI, LAURENT; TEPLYAKOV, ANDREW V.

JOURNAL OF PHYSICAL CHEMISTRY B - (Print)

AMER CHEMICAL SOC

Año: 2006 vol. 110 p. 14337 - 14344

1520-6106

The surface chemistry of 1,1,1,5,5,5-hexafluoro-2,4-pentanedione (hfacH), a hydrogenated form of the most common ligand in metal and metal oxide deposition, on Si(100)-2×1 has been investigated using multiple internal reflection Fourier transform infrared spectroscopy (MIR-FTIR), Auger electron spectroscopy (AES), thermal desorption mass spectrometry, and computational analysis. The main goal of these studies was to understand if hfacH is a source of fluorine, carbon, and oxygen contamination for a variety of deposition processes where the hfac ligand is involved. In its molecular form, hfacH may potentially have up to 10 isomers including two ketonic and eight enolic forms. One of the enolic forms is shown to be the most stable upon adsorption on a clean Si(100)-2×1 surface at submonolayer coverages at cryogenic temperatures. Even though only the enolic form is present at cryogenic temperatures, at room temperature any of these isomers can exist and all the possibilities of their interaction with the Si(100)-2×1 surface, including several [2 + 2] and [2 + 4] addition pathways as well as o-H dissociation, should be considered. Despite such an array of possibilities, the room-temperature adsorption is governed by the thermodynamic stability of the final addition products between the hfacH and silicon surface. These adducts are stable at room temperature and decompose upon surface annealing. © 2006 American Chemical Society.