Gas Feed In


RF Source


Pump Out


Figure 3. A simple plasma reactor consisting of opposed parallel plate electrodes in a
vacuum chamber. There is a continuous gas feed in and a port for pumping out. A
radio frequency power source is coupled to the electrodes to generate a plasma. [3]






 Plasma
 + + + + + +


- - - -


Sheath


 Substrate


 Electrode

Figure 4. The plasma sheath. The diffusion of electrons from the gas adjacent to the
sample to the walls or surfaces creates a positive layer called the sheath. The
accumulated negative charge on the substrate attracts the positive charges of the
sheath which accelerate towards and strike the the substrate a near-normal incidence.
This produces vertical sidewalls.