AVS 49th International Symposium
    Organic Films and Devices Wednesday Sessions
       Session OF+EL-WeP

Paper OF+EL-WeP7
Characterization of OLED Degradation by Emission Microscope

Wednesday, November 6, 2002, 11:00 am, Room Exhibit Hall B2

Session: Organic Films and Devices
Presenter: N. Miura, ITES Co. Ltd., Japan
Authors: N. Miura, ITES Co. Ltd., Japan
Y. Luo, ITES Co. Ltd., Japan
K. Takagi, ITES Co. Ltd., Japan
Correspondent: Click to Email
The purpose of this study is to investigate how an emission microscope has been applied to evaluation for the degradation mechanism of organic light-emitting devices (OLED). One of the most effective ways to characterize OLED degradation is to study a physical and chemical phenomenon that occurs with an exact point of interest. The problem, however, is one of isolating the exact point of degradation. Thickness of a luminescent layer is around 0.1 microns. Consequently, a less-than-0.1-micron foreign matter can become a cause of an electrical short failure. On the other hand, a size of a pixel is the approximately one hundred microns. Therefore pinpoint detection of a failure location is extremely difficult. In order to solve this problem, an emission microscope used for a failure analysis of Si-based LSIs has been applied to detect a degradation point in plane luminescent devices. An emission microscope is a tool to detect a faint light emitting at a failure point with PMT or CCD camera and to find out a point of interest by adding an optical image and a detected one. This study describes a method for applying emission microscope in the failure analysis of OLED and demonstrates the effectiveness of this method. It is confirmed that an observation under sub-threshold bias condition is effective to find out a failure point. Although no electro-luminescence is observed under this condition with an optical microscope, an emission microscope can get detect a photon emission at a failure location. Some case studies are described to demonstrate the effectiveness of this method. Cross sectional TEM observations of defects located with this technique are also included.