Dual-frequency inductively coupled CH

4

plasma is often used in the deposition of carbon-based films. The carbon dissociation characteristics of the plasma during deposition are the most important factors affecting the properties of the films. Based on emission spectroscopy and response surface method

the carbon dissociation characteristics of dual-frequency inductively coupled CH

4

plasma under different reaction gas flow rates are investigated. The transition of dissociation dominant reaction is found and the dissociation transition mechanism is revealed. Also

the turning point of CH

4

flow rate in transition is me

asured and the influences of auxiliary gases Ar and H

2

on the dissociation transition are discussed. The results show that the turning flow rate of CH

4

is 5.8 sccm. When the flow rate is higher than 5.8 sccm

CH

4

dissociates and and generates CH group. When the flow rate is lower than 5.8 sccm

CH dehydrogenates further to generate C. Ar will promote the dissociation of CH

4

resulting in an increase in CH

4

turning flow rate. Low flow rate (

<

35 sccm) H

2

will inhibit the dehydrogenation of CH

resulting in a decrease in CH

4

CH

4

turning flow rate. While high flow rate (

>

35 sccm) H

2

will inhibit the generation of CH

resulting in an increase in CH

4

turning flow rate. This research is of great significance to the optimization of plasma processes.