Box Cathode Sputtering Technologies for Organic Optoelectronics

유기물 광전소자 제작을 위한 박스 캐소드 스퍼터 기술

We report on plasma damage free-sputtering technologies for organic light emitting diodes (OLEDs), organic thin rim transistor (OTFT) and flexible displays by using a box cathode sputtering (BCS) method. Specially designed BCS system has two facing targets generating high magnetic fields ideally entering and leaving the targets, perpendicularly. This target geometry allows the formation of high-density plasma between targets and enables us to realize plasma damage free sputtering on organic layer without protection layer against plasma. The OLED with top cathode prepared by BCS shows electrical and optical characteristics comparable to OLED with thermally evaporated Mg-Ag cathode. It was found that TOLED with ITO or IZO top cathode layer prepared by BCS has much lower leakage current density ($1\times10^{-5}$ mA/cm2 at -6V) than that ($1\times10^{-1}\sim10^{\circ}mA/cm^2$)of OLED prepared by conventional DC sputtering system. This indicates that BCS technique is a promising electrode deposition method for substituting conventional thermal evaporation and dc/rf sputtering in fabrication process of organic based optoelectronics.