Study On Growth And Structure Of A-C:H Films Prepared By An Inductively Coupled Micro-plasma Jet

A miniaturized radio-frequency-driven inductively coupled plasma jet source with 13.56MHz has been developed and its application to deposit hydrogenated carbon films from CH₄ and H₂ on silicon or glass wafers has also been studied. Plasma jet was generated in a quartz glass tube with a water-cooled antenna around it. Langmuir probe has been used to test the plasma characteristics such as electron temperature, electron density and ion density. ET-350 profilemeter, Raman spectrum, FTIR and UV-VIS spectrum are used for analysis of the films such as the film growth rate, Raman structure and optical energy gap with different power, negative bias and gas flow ratio R [R=H₂/(H₂+CH₄)]. It is found that the highest growth rate can be reached at 1.1μm/min at the input power of 250W; The Raman spectra are characterized by D-peak and G-peak at about 1350 cm^-1 and 1580cm^-1, which shows the as-deposited film as a typical DLC .The structure of carbon in the films is mainly composed of sp²,sp³ and polymerlike forms. As the input power and bias increase, polymerlike carbon is broken into sp² and sp³, so the fluorescence signal of the Raman spectrum decreases; The decreased FWHM indicates that the order of the films has been improved, but the I_D/I_G presentes two different trends; As the R increases, the I_D/I_G decreases, while the E_g increases, which confirmes the structure change of the films from GLC to DLC.