Thermal Desorption Spectroscopy and X-Ray Photoelectron Spectroscopy Study of CFx Layer Deposited on Si and SiO2

Abstract

Thermal reactions between a fluorocarbon ( CF _x ) layer formed with C₄F₈ magnetomicrowave plasma and Si and SiO₂ are studied by thermal desorption spectroscopy (TDS). Atomic compositions and core spectra of the CF _x layer are measured by temperature-programmed X-ray photoelectron spectroscopy (TP-XPS) with concomitant desorption gas species analysis by quadrupole mass spectrometer. The TDS study reveals that the primary reaction products are SiF₄ in Si and SiF₄ and CO in SiO₂, and F generated from the CF _x layer is a primary reactive species contributing to the formation of the reaction products not only in Si but also in SiO₂. The TP-XPS study reveals that the drastic decrease of F/C ratio agrees with the desorption of SiF₄ and CO.