If I have an Au thin films which 300 A thick and evaporated by thermally deposited, since 5 years and now a strange spots appear on them, and i want to make them as a contact for SnO2 which will prepare by spry pyrolysis. can i use these gold Films and how can i etching them.
Hi Mohammed,
Would you like to send an optical image of the spots to RG? We can help you better of we see what it looks like. Did you characterize their roughness and compared with the previous electrodes you evaporated? Or did you do EDS analysis for the chemical composition on and in the vicinity of these spots?
What do you want to etch? SnO2 or Au?
As Dilek suggested attach a optical image of the spots. i will suggest you to wash it with chemical like Acetone if that are the dust spots it will be cleaned. i am also using Au for electrode its metal and Au u can use it after long time. Can u tell where u keep these films for long time In open room or in vacuum box. i usually keep slides in vacuum box. If you want to etch u can do it with wet etching the solution i am using is the Mixtures of nitric acid and hydrochloric acid (in a mixing ration of 1 : 3 also called aqua regia) {HCl : HNO3 (3:1)}.. at an etching rate of approx. 50°A/s (at temperature of 50°C)
Dear delik Lsik
thank you for intresting at first i want to etch the Au films and may be i can test them by optical microscope and send you the images, but i do not have EDS, but i would like to ask you again, what do you expect about these spots, if i kept them in air.?
best regards
M.Razooqi
Dear Mir Waqas
Thank you for interest. really i kept the Au films in air not in vacuum. and i am afraid that the way of etching is benifit but it will remove a large size of films, where it is 300 A thick, and this mean it will remove i 6 seconds, anyway i will try the Aceton way, but i would like to ask you again, must i use the ultrasonic bath with aceton or not?
thanks alot
M.Razooqi
From your description in your question, one feels that these spots were formed during evaporation process.
If it is not the case you can go to the optical microscope take images and then do sonication in acetone or isopropanol and dry them with nitrojen jet. Afterwards you can check them under microscope again. If it remains after cleaning you can try oxygen plasma...
Good luck!
Note: Please take care when writing my name and see how you wrote it in your first answer.
i think its because of keeping film in air . may be its dust particle . do ultrasonically washing with Acetone and isopropanol as Dilek Isik described. and lets see if any change occurred. i also suggest you after washing do backing for few minutes at temperature of around 80°C. Don't do etching, with in second it will etch your all films . Oxygen plasma is better.
Best Of Luck
Dear Dilek
thank you very much and i am sorry about writing your name i will writ it carefully next time
Best Regards
m.Razooqi
Dear Mir Waqas
thank you very much and i will try your advice about ultrasonic bath with acetone and under 80 C. but i dont know what is the oxygen plasma.
Best Regards
M.Razooqi
Your welcome dear
Oxygen plasma treatment is also another safe and environmentally friendly cleaning method .alternative to traditional cleaning methods.
You can check this link
http://www.astp.com/plasma-equipment/applications
U can also search on google about that...
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