发光二极管可靠性的噪声表征

通过对发光二极管内部结构的研究，发现N_t(界面态陷阱密度)和扩散电流比率 是影响发光二极管性能的重要因素，并与器件可靠性有密切关系.器件内部存在的多种噪声 中，低频1/f噪声可表征N_t和扩散电流比率.在深入研究发光二极管工作原理及1 /f噪声载流子数涨落理论和迁移率涨落理论的基础上，建立了发光二极管的电性能模型及1/ f噪声模型.在输入电流宽范围变化的条件下测量了器件的电学噪声，实验结果与理论模型符 合良好.通过对其测量结果分析，深入研究了噪声和发光二极管性能与可靠性的关系，证明 了噪声幅值越大，电流指数越接近于2，器件可靠性越差，失效率则显著增大. 关键词： 1/f噪声 发光二极管 陷阱 光功率

Noise as a representation for reliability of light emitting diode

Through the research of the internal structure of Light Emitting Diode (LED), we discovered that the interface trap density and diffusion current ratio are key factors determining the performance of LED, and they are also closely related to the reliability of LED. Among the many kinds of internal noises in LED, low-fre quency 1/f noise describes the interfoce trap density and diffuse current ratio effectively. Based on the mechanism of carrier number fluctuation and carrier mo bility fluctuation of 1/f noise, we put forward the electrical model and 1/f noi se model of LED. We also measured the electrical noise of the device over a wide range of current. Experimental results agree well with the proposed model. Usin g the experimental data, the relationship between noise and the performance and reliability of LED is established. It is proved that the larger the noise magnit ude, the nearer the current exponent is to 2, leading to the degradation of devi ce reliability and significant rise in device invalidation rate.