[[Plasma generation#Capacitive coupling|Capacitively]] coupled PECVD systems have one primary RF power supply, used to generate the plasma, but may have additional power supplies which allow further modification of the film properties.
Primary RF Power
* Typically high frequency (HF) RF power at 13.56 MHz frequency
* Used to disassociate ("crack") the reactant gases and generate the plasma
* Strong effect on film stress
Secondary (bias) RF power
* Typically a low frequency (LF) RF power at less than 500 kHz frequency
* Causes more ion bombardment of the sample surface