Dielectric substrate self-bias and plasma confinement in two-dimensional scanning radio frequency plasma-enhanced chemical vapour deposition

A two-dimensional scanning radio frequency (RF) plasma method was developed for large area deposition in order to avoid difficulties encountered in conventional large RF plasma systems, offering precision control of plasma, improved uniformity of thickness and microstructure, and simplicity of system design. Guarded electrode houses were introduced to form localized plasma thus parasitic plasma or parasitic deposition outside the localized plasma region was eliminated. Different electrode configurations were studied and optimized. Self-bias on dielectric substrate was studied for different electrode configurations as a function of RF power, pressure, and gases. Eliminating parasitic plasma by fully shielding the basing electrode resulted in monitoring signal losses of self-bias. Introducing an isolated plasma house for the biasing electrode enabled the recovery of the self-bias on the biasing electrode without parasitic deposition on substrate outside the localized plasma region. Uniformity optimization within the localized plasma region is no longer a concern in this system. Thickness profile control was achieved by scanning the plasma source over the large substrate. TEM analysis showed that homogenous films were deposited in the scanning deposition system.