A passive matrix addressed organic electroluminescent display using a stack of insulators as row separators

In order to use the impressive performances of organic Light emitting diode s (OLEDs) in high-resolution flat-panel displays (FPDs), ways must be found to circumvent their incompatibility with standard microfabrication techniq ues. To integrate organic compounds in a passive matrix, one must be able t o pattern the top electrode in rows without exposing them to any processing . We deposited a stack of three different insulators in one process in a co mmercial plasma-enhanced chemical vapor deposition (PECVD) tool, patterned it in a single lithography step and in a single wet etch step. The top insu lator etches slowest, so the stack gets undercut. When organics and the top electrode are thermally evaporated on this pattern, they are physically di scontinuous at the edges of the overhanging insulator. The lowest insulator etches slower than the middle one, so it tails out and prevents short circ uits when the top electrode flows over the edge of the organic layers. This process combines simplicity and high resolution, two prerequisites for OLE Ds to compete with existing FPD technologies. (C) 2000 Elsevier Science S.A . All rights reserved.