不同表面结构的半导体发光二极管的效率与寿命的研究

Study of light efficiency and lifetime of LED with different surface structures

对GaAs基AlGaInP系半导体发光二极管(light emitting diode,LED)提取效率低导致器件发热而寿命缩短等问题进行了分析,提出了一种新型表面结构的LED,在与普通LED相同的外延生长条件下,通过后工艺引入了表面图形并腐蚀出凹凸不平的表面以改变光子传输方向,同时制备了导电光增透层,既增强了电流的扩展同时使得更多的光子能够发射到体外,在相同的注入电流下,新型表面增透结构LED的轴向光强平均是普通LED的1.5倍,由于光提取效率高,更多的光子能够发射到体外,发热减少,饱和电流更高,达到125mA,加速老化寿命测试显示:裸芯寿命为19×104h,封装后寿命为13×104h,器件适合于大电流下工作.

The main problem of GaAs based AlGaInP series LED is the low light extraction efficiency and heat generation inside, which have serious impact on the LED＇ lifetime. In this paper, we introduce a kind of LED with new surface structure formed of surface texture and light anti-reflecting layers through the post-epitaxial processing. In this new structure, the inside light transmission route has been changed and the current spreading is enhanced, which makes much more light emit outside. With the same injected current, the new LED＇ output light intensity is in average 1.5 times as the normal LED with the same epitaxial structure, and the ratio is larger than 1.5 as the injected current increases. The new LED＇ s saturation current is as high as 125 mA because of the heat is decreased inside, the accelerated aging test shows that the new LED＇ lifetime is as long as 13 ×10^4 h for packaged ones and 19 ×10^4 h for unpackaged ones, which is suitable for working at large injected current especially.