Deposition of top Al electrode films by a low damage Facing-Target sputtering method (FTS) have been attempted to fabricate an Organic Light Emitting Diode (OLED) (glass substrate/ITO /NPB/Alq₃/BCP/LiF/Al). Suppression of the high energy secondary electron incidence to the substrate during the sputter-deposition of the aluminum electrode films was effective to reduce the light emitting voltage and improve the luminance efficiency of the OLED. In addition, optimization of sputtering gas pressure and reduction of the sputtering current was necessary in the deposition the electrode films to obtain the OLED with good performance. Compared with the OLED fabricated by vacuum evaporation, the OLED fabricated by our low damage sputtering system at the optimum conditions showed better injection current-luminance efficiency, although it had a little bit larger operating voltage.

View full abstract