I have an ITO (In:Sn = 90:10) target and prepared a 150nm thin film on a glass substrate through RF sputtering under conditons Ar : O2 = 20: 2 sccm with 100W power. I tried to measure the resistance of a commercially available ITO glass substrate with simple multimeter which is around 20-30 ohm. Whereas the resistivity of home made ITO coated glass is very high behaving like an insulator. Can someone help me how can I decrease the resistivity and prepare a conducting thin film on a glass substrate?
Clean both the glass surfaces, choose suitable spacer as you need the thin film thickness, choose materials, monomers of conducting polymers, crosslinker, add UV or Vis-light initiator to cure and crosslinked to form the film . You may alsofabricate a metal or metal oxide conductive thin film onto the glass-substrate.
Article Electrodeposition of platinum on metallic and nonmetallic su...
http://www.tissueeng.net/lab/papers/Metallic%20glass%20thin%20films%20for%20potential%20biomedical%20applications.pdf
Please also take into account that most of the ITO films applied are annealed, to reduce the number of defects and to increase the electrical conductivity.
Either you have to post-heat treatment (annealing) as suggested by Mr Mitterer, or you have to heat the substrate while depositing the film...partial pressure of oxygen (flow rate of O2) must be critical where the deposition rate would define the film property...
Just use Argon as the sputter gas as a starting point, I have acheived < 30 ohm/sq.. The process pressure also influences the conductivity, try 8mT. You will also find differences between suppliers of the ITO target. Having a bit of oxygen in the gas helps presserve the oxygen content in the target put too much in the process gas will decrease the film conductivity.
Increase the thickness of the prepared film to 300 nm and after deposition you have to do annealing to oxidize the film by rapid thermal processing for 5 minutes in the presence of oxygen gas. The resistance will decrease from kilo ohms to less than 100 ohm, depending on the thickness.
1- I have obtained 300-400 ohm resistance for a glass coated under these conditions.
75W RF power
30 sccm Ar
500C annealed for 1 hour.
200 mm thickness
Whereas for plastic substrate under same conditions the sheet resistance is about 10kohm.
Can you suggest me any idea for reducing resistance less than 100 ohm. Specially for plastic PET substrate we can't aneal it.
Dear, you simply have too high concentration of O2 in the gas flow. Most processes need between 1.5 and 2% of O2 in the gas flow... you have 10%.
- Badges
- Science topic
- Similar topics
- Physical Sciences
- Materials Science
- Materials
- Inorganic Materials
- Ceramics
- Glass