ITO Surface Flatness
26/07/2013 09:18
Section IV, OLED key process
First, indium tin oxide (ITO) substrate pretreatment
(1) ITO Surface Flatness: ITO has been widely applied in the commercial manufacture of display panels, which has a high transmittance, low resistivity and high work functions, and so on. In general, the use of radio frequency sputtering (RF sputtering) manufactured ITO, process control factors susceptible to surface irregularities due to poor and, thus, the surface of the substance or projection tip.
Another high-temperature calcination and recrystallization process will produce surface projections about 10 ~ 30nm layer. The fine uneven layer is formed between the path of the hole directly at the cathode will be provided the opportunity to make these intricate paths increase in leakage current. Usually there are three ways to solve this surface layer of? U One is to increase the hole injection layer and the hole transport layer has a thickness in order to reduce the leakage current, this method is used for thicker layers and the hole PLED OLED (~ 200nm). Second, the ITO glass recycling process, make the surface smooth. Third, the method makes use of other coating surface flatness better.
(2) ITO work function increases: When the hole injection from the ITO HIL, the potential energy difference is too large will produce Schottky barrier, making the hole injection is not easy, so how to reduce the ITO / HIL interface potential energy difference becomes ITO pretreatment of focus.
