Deposition of an Al cathode for an OLED by using low-damage sputtering method

In this study, At thin films for OLED devices were deposited on glass substrates and on a cell (LiF/EML/HTL/bottom electrode, ITO thin film) for various working gas such as Ar, Kr and mixed gases, and various working gas pressures. The film thickness and the crystallographic and electrical properties of the At thin film were measured by an a-step profiler (TENCOR), an X-ray diffractometer (XRD, RIGAKU), a four-point probe (CHANGMIN) and an atomic force microscope (AFM), and the I-V curve of the Al/cell was measured by using a semiconductor parameter measurement (HP4156A). The crystallinity and resistivity of At thin films prepared on glass indicated that the films were amorphous with resistivities under 10(-5) Omega-cm. In the case of the At thin films deposited on cell using pure Ar or Kr, the leakage-current density of the Al/cell was about 10(-4) mA/cm(2), and the leakage-current density of the Al/cell prepared by using Ar and Kr mixed gas was about 10(-6) mA/cm(2).