| Summary: | 碩士 === 國立暨南國際大學 === 應用材料及光電工程學系 === 102 === In this thesis, we present a technique to quickly investigate the lifetime and reliability of light emitting diode by using the reverse-bias stress, and the devices were operated in dry air, water vapor and salty water condition. The current-voltage (I-V) curve were measured with the Agilent 4155C semiconductor parameter analyzer. The electroluminescence image and optical characterizations were measured with low temperature CCD optical microscope and integrating sphere. The material characteristics of the LEDs were analyzed by scanning electron microscopy (SEM), energy dispersive spectrometers (EDS), secondary ion mass spectrometer (SIMS) and Low Frequency Noise (L-F Noise). The current-voltage (I-V) curve on a logarithmic scale analysis can be clearly observed the behavior of degradation, such as threshold voltage change, resistance and parallel resistance effect. The result indicates that the carrier transport mechanism by semiconductor surface states, or devices in the bias caused by the gradual increase in the deep defect eventually led to failure, and electromigration may cause LED generate damage, due to the diffusion of metal atoms. These techniques were proposed to describe an actual optical degradation and detect the device failures with the fabrication process for future industrial applications.
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