Nowadays most of the high resolution displays for smart phones use the cost-intensive LTPS technology. Even the new IGZO sputtering technology cannot reach a cost level sufficient to be competitive with a-Si technology. The expectation of panel makers is to bring the IGZO technology costs to a level where it can compete with amorphous silicon. Current processes demand an additional etch-stop layer (ESL), which requires at least one more mask, as well as new PECVD equipment with new specifications. Typically PECVD silicon dioxide or silicon nitride is widely used as ESL; but because of the higher hydrogen concentration in the PECVD layer, the device stability and lifetime degrade dramatically.
Evonik is developing, under our brand iXsenic ES, unique electronic grade etch-stop material with photo-patternable characteristics and a hydrogen-free layer that is suitable for sputtered and solution-processed metal-oxide semiconductors. Evonik hybrid polymers have significant advantages in high chemical resistance, high uniformity and high transparency. They allow easy implementation directly in the production line with no additional investment costs for new PECVD equipment.
In combination with the solution-processable metal-oxide ink iXsenic S, our photo-patternable solution-processable etch-stop layer will further contribute to a decrease of investment and production costs.