Plasma-enhanced chemical vapor deposition reactors and associated methods
Plasma-enhanced chemical vapor deposition (PECVD) reactors and methods of fabricating polymers via PECVD processes are generally provided. In some embodiments, a PECVD reactor has one or more features that enhance the quality of the polymers that may be formed therein. Similarly, some methods are performed in a manner that enhances the quality of a polymer formed thereby.
1 . A plasma-enhanced chemical vapor deposition (PECVD) reactor, comprising:
a deposition chamber,
wherein the deposition chamber is enclosed by a plurality of walls;
wherein the plurality of walls comprises a bottom wall and sidewalls surrounding the bottom wall;
wherein a plasma electrode is positioned inside the deposition chamber above the bottom wall, and wherein a ratio of a spacing between the plasma electrode and its closest sidewall to a spacing between the plasma electrode and the bottom wall is selected to allow flow of a precursor gas to be laminar or substantially laminar; and
a control system, wherein:
the control system is configured to control one or more of a composition of the precursor gas, a flow rate of the precursor gas, a pressure inside the deposition chamber, and/or a power supplied by the plasma electrode, and
the control system is configured to maintain a total energy to which a monomer flowing through the deposition chamber is exposed at a value that is greater than or equal to 1.5×10 −24 J/molecule and less than or equal to 32.0×10 −24 J/molecule.
2 . The PECVD reactor of claim 1 , wherein the ratio of the spacing between the plasma electrode and its closest sidewall to the spacing between the plasma electrode and the bottom wall is greater than or equal to 0.1 and less than or equal to 0.4, greater than or equal to 0.1 and less than or equal to 0.3, greater than or equal to 0.15 and less than or equal to 0.4, greater than or equal to 0.12 and less than or equal to 0.4, greater than or equal to 0.12 and less than or equal to 0.3, or greater than or equal to 0.12 and less than or equal to 0.2.
3 . The PECVD reactor of claim 1 , wherein the deposition chamber further comprises an inlet, wherein the inlet takes the form of a showerhead through which the precursor gas is introduced into the deposition chamber.
4 . The PECVD reactor of claim 3 , wherein the inlet is a ground electrode.
5 . The PECVD reactor of claim 3 , wherein the showerhead comprises a plurality of apertures through which the precursor gas is introduced into the deposition chamber, and wherein the apertures are positioned around an aperture-free region.
6 . The PECVD reactor of claim 3 , further comprising a premixing zone positioned upstream from the inlet, and wherein the premixing zone is configured such that two or more sources of gas are capable of mixing to form the precursor gas.
7 . The PECVD reactor of claim 6 , wherein a ratio of the volume of the premixing zone to a volume of the deposition chamber is greater than or equal to 0.06 and less than or equal to 0.15.
8 . The PECVD reactor of claim 1 , wherein the plasma electrode is configured to supply plasma at a power density of greater than or equal to 0.01 mW/in 3 and less than or equal to 0.6 mW/in 3 .
9 . The PECVD reactor of claim 1 , wherein a spacing between the bottom wall and the plasma electrode is greater than or equal to 2 inches and less than or equal to 5 inches.
10 . The PECVD reactor of claim 1 , wherein the plasma electrode has a cross-sectional area that occupies greater than or equal to 80% of the cross-sectional area of the deposition chamber.