Utilization of a buffer layer of siliconcarbon oxide or zinc oxide between the ITO and the substrate has been shown to improve mechanical performance. Adding a buffer layer between the ITO and substrate layers can improve the bend radius by greater than 30%, with minimal changes in optical transparency or electrical resistivity.
Proprietary inks can be used in the same manner, enabling a very flexible layer to be deposited without the characteristics of the sputtered product. Annealed ITO nanoparticle coatings have demonstrated improved material flexibility compared with traditionally sputtered ITO, giving more options for those applications requiring a greater range of motion.
Promising advanced sputtering techniques like HiPIMS (high-power impulse magnetron sputtering) produce better bending characteristics and wear resistance due to the different film characteristics, including a finer grain structure, enabling deep trench filling. Substrate temperatures remain low with the HiPIMs process compared to other metal oxide deposition techniques. This is clearly an advantage when depositing ITO onto flexible, temperature-sensitive materials.
This work was done by Dr. Andrew Guistini of Dartmouth College; Dr. Ronald Lasky of Dartmouth College and Indium Corporation; and Dr. Robert Ploessl, Malcolm Harrower, and David Socha of Indium Corporation. 49745-122