【作者】 苏丽伟；

【导师】 江风益；

【作者基本信息】 南昌大学 ， 材料物理与化学， 2008， 硕士

【摘要】 近几年来,在硅(Si)衬底上生长GaN材料已经取得了很大的进展,并已制作出功率型的Si基GaN蓝绿光发光二极管(LED)。众所周知,器件的可靠性直接关系到技术的商业价值与产业化,因此,Si基GaN LED可靠性的研究就显得尤为重要。然而Si基GaN LED作为一种全新的产品,其可靠性仍需做进一步的研究与分析。本文主要研究了Si基GaN LED芯片在大电流老化下的光电性能和抗静电性能。获得了如下一些有意义和部分有新意的结果:1.对200μm×200μm的LED芯片和400μm×600μm的功率型蓝光LED芯片分别进行大电流老化实验,得出500mA、5min和1A、15min分别为上述两种芯片的优化老化条件,且其老化结果与常规老化电流老化的结果吻合较好。2.用人体模式和机器模式两种模式对GaN/Si LED芯片进行静电打击,结果表明200V机器放电模式和1200V人体放电模式下的效果是相近的,且机器放电模式下的试验条件更为苛刻,因此ESD实验一般选择人体放电模式。而且在人体模式下,不同的ESD电压对老化结果没有显著的影响。3.对比有无反射镜的功率型蓝光LED芯片(芯片尺寸400μm×600μm)进行1200V人体放电模式的静电击打试验,两者的静电通过率接近,说明反射镜的制作在提高光强的同时对芯片的抗静电性能影响不明显。4.对本实验室在Si(111)衬底上MOCVD法生长的芯片尺寸为400μm×600μm功率型绿光LED的光电性能进行研究。带有银反射镜的LED在20mA的电流下正向工作电压为3.59V,主波长518nm,输出光功率为7.3mW,90mA下达到28.2mW,发光功率效率为7.5%,光输出饱和电流高达600mA。200mA电流加速老化216小时后,有银反射镜的LED光衰小于无银反射镜的LED,本文把这一现象归结于Ag反射镜在提高出光效率的同时,降低了芯片本身的温度。以上研究结果已经在本实验室产业化基地晶能光电(江西)有限公司硅衬底LED质量表征中采用。更多还原

【Abstract】 Recently,growth of GaN on Si substrate has made great progress,it is reported that high power GaN/Si LED have been fabricated.It is known that the reliability of devices is connected to commercial value and manufactory of an technology,so study on properties of GaN/Si LED is far from important.But as a brand-new product, study and analysis on GaN/Si LED is still needed.In this dissertation,photoelectric and electrostatic discharge properties of GaN based LED chips on Si substrate after aging at high direct current are studied.Some significant and innovative results achieved are following:1.Accelerated aging experiment was carried for LED chips of 200μm×200μm and high power LED chips at high direct current respectively.The results show that 500mA test current in 5min and 1A test current in 15min are the proper test condition, and the results of large current accelerated aging experiment are matched well with ordinary test current.2.GaN/Si LED chips were stroke by human being mode(HBM) and machine mode(MM) electrostatic discharge,results show that the effect of ESD of 200V MM is close to ESD of 1200V HBM,while the effect of the former is shaper,so HBM is commonly chosen in ESD experiment.Different ESD voltage doesn’t influence the accelerated age experiment in HBM.3.High power blue GaN/Si LED chips(400μm×600μm) with and without reflector were stroke by 1200V(HBM) and the pass rate of the two are closed which show that Ag reflector can raise the light output and have no influence on the ESD.4.Study was carried on optical and electrical characterization of high power green LED on Si(111) substrate by MOCVD with chip dimension of 400μm×600μm in our laboratory.The forward bias of the LED with Ag reflector is about 3.59 V under 20 mA,the light output power is about 7.3 mW with dominant wavelength of 518 nm,the light output power achieves 28.2mW under 90mA,the light output efficiency is 7.5%,the saturate output current was as high as 600mA.The light degradation of LED with Ag reflector was smaller than LED without Ag reflector after 216 hours accelerate aging test under 200mA,this phenomenon was induced by Ag reflector,which can raise the light extraction efficiency and lower the temperature of the chip itself.The results of above all have already been applied in LED test of Lattice Power (Jiang Xi) Corporation.This work is supported by 863-project of China and electronic development program in China.更多还原