Method of low-temperature plasma generation, method of an electrically conductive or ferromagnetic tube coating using pulsed plasma and corresponding devices
The present invention resides in the unifying idea of synchronizing a positive voltage pulse supplied to an electrically conductive or ferromagnetic tube and a exciting negative voltage pulse on a hollow cathode induced on the background of a high-frequency capacitive discharge. In one embodiment, the invention relates to a method of generating low-temperature plasma in a vacuum chamber comprising a hollow cathode and an electrode, the method comprising the step of igniting the pulsed DC discharge in the hollow cathode wherein the positive voltage pulse at least partially overlaps with the negative voltage pulse, and the positive voltage pulse at least partially overlaps with the negative voltage pulse on the hollow cathode. In another embodiment, the present invention relates to a method of coating the inner walls of hollow tubes which utilizes the above-mentioned low-temperature plasma generation process. In another embodiment, the invention relates to a low-temperature plasma generating device comprising a hollow cathode located in the vacuum chamber, a RF plasma source, a pulse DC burst source, and a bipolar pulse source. In another embodiment, an object of the invention is an apparatus adapted to coat the inner sides of hollow tubes comprising a low-temperature plasma generating device.
1. A device for generating a pulsed discharge low-temperature plasma comprising
a DC pulse source connected in parallel to a RF source;
an electrode and a hollow cathode placed in a vacuum chamber,
a bipolar source synchronized with the DC pulse source via a control pulses generator, wherein
the electrode is connected to the bipolar source, wherein the bipolar source is configured to apply a positive voltage pulse on the electrode; and
the hollow cathode is connected to the RF source and the DC pulse source, wherein DC pulse source is configured to initiate a pulse discharge on a background of RF capacity discharge; and wherein
the device is configured to set the positive voltage pulse on the electrode in at least in part overlap with a negative voltage pulse applied on the hollow cathode.
2. A device suitable for coating an inner surface of an electrically conductive or ferromagnetic hollow tube by a thin film via low-temperature plasma comprising the device according to claim 1 ,
wherein,
the hollow cathode is a coated tube situated in a vacuum chamber,
the electrode is equipped with a hollow cathode at its end; and
the hollow cathode and the coated tube are electrically insulated.
3. The device according to claim 2 , wherein the coated tube is attached to a cooling.
4. The device according to claim 3 , wherein the cooling is a water cooling.
5. The device according to claim 4 , wherein the water cooling is attached to a bellows, wherein the bellows are electrically insulated from sides of the vacuum chamber.
6. The device according to claim 4 , wherein the device further comprises at least one oscillography probe connected to a digital oscilloscope and the electrode and/or the water cooling.
7. The device according to claim 4 , wherein the water cooling is connected to a low-frequency filter via measuring resistance, wherein the low-frequency filter is consisting of inductor and capacitor with the bipolar pulse source.
8. The device according to claim 2 , wherein the vacuum chamber further comprises at least one opening for entrance gas flow.
9. The device according to claim 2 , wherein the electrode is equipped with a water cooling.