We both have deficient S content by using co-sputtering with WS2 and graphite targets and reactive sputtering with WS2 target and acetylene gas. Do you know how to resolve this problem， yes the literature indicated that this may be caused by bombardment of argon and reactions of Hydrogen and S to H2S, which consumes S content, however we tried many experiments with different parameters, the S/W ratio is mostly below 1. Looking forward to your warmhearted replies. Great thanks.
hello!
WS2 is an excellent solid lubricant in dry conditions. You should use the following procedure and operating condition:
Try to use pulsed, DC magnetron sputtering from a sintered WS2 target. Say for a 4 inch target.
Use power in the range 450-600 W. Important thing is sample preparation:
Try to use single-crystalline (1 0 0) silicon wafer as the substrate. Put your sample in side the chamber. You have to preclean by Argon etching for 20 minute at a high bias voltage of -600 to 700 V. keep the discharge pressure at 4-5 mTorr.
After precleaning, make the pressure at 4-5 mTorr. keep the sample at floating potential (substrate should not be grounded). Also, do not use any substrate bias.
Make the samples with (about 300-700 degree) and without heating.
2nd method with H2S + Ar
Since H2S contains an oxidizing (Sulphor) as well as a reducing component (H) it is not clear whether the required sulfurization really occurs.
Then you have to check the effect of the ratio of H2S and Ar. Try to put H2s 10-50 % of Argon and make additional sulfur in the sputtering atmosphere that can lead to a better repair of sulfur vacancies which are induced by energetic particle bombardment.
3rd trial: try to Use RF power of 13.%^ MHz or 27.56 MHz, which can enhance the H2s dissociation and ionization of Ar and H to give more S for your purpose.
Good luck
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