快速热退火工艺对工业生产红光LED芯片性能的影响

Influences of rapid thermal annealing on the performance of red LED chips

采用电子束蒸发工艺在GaAs基LED外延层上制备了氧化铟锡(ITO:Indium Tin Oxide)薄膜,采用快速热退火(RTA:Rapid Thermo Annealing)工艺制备ITO薄膜与GaAs外延层的欧姆接触。研究了退火温度、退火时间对ITO薄膜性能以及LED芯片性能的影响。结果显示:固定退火时间8s时,ITO薄膜方块电阻呈减小趋势,但变化不大,430℃时为7.7Ω/□;LED芯片亮度LOP呈现非线性先上升后下降趋势,430℃时达峰值136mcd;外延片背面欧姆电阻呈现先下降后上升抛物线趋势,440℃时达谷值1.13Ω。固定退火温度415℃时,LED芯片亮度LOP呈现非线性先上升后下降趋势,退火12s时达峰值132.5mcd;外延片背面欧姆电阻呈现先下降后上升抛物线趋势,退火12s时时达谷值0.93Ω。

ITO (Indium Tin Oxide) thin films were prepared on GaAs-based LED epitaxial layer by electron beam evaporation.And the ohmic contact between ITO thin films and GaAs epitaxial layer was deposited by rapid thermal annealing.The effects of annealing temperature and time on the property of ITO thin films and LED chips were studied.The results show that the resistance of ITO film decreases weakly.When fixing the annealing time of 8s,at 430℃,the resistance of ITO thin film is 7.7Ω/□,the LOP,parameter of LED chip brightness shows a non-linear trend of first rising and then falling,reaching the peak value of 136mcd,at 430℃,the ohmic resistance on the back of LED chip shows the trend of first falling and then rising,reaching a valley value of 1.13Ω at 440℃.When fixing the annealing temperature of 415℃,the lop of LED chips shows the trend of first rising and then declining,reaching the peak value of 132.5mcd at annealing 12s,the ohmic resistance on the back of LED chip shows the trend of first falling and then rising,reaching a valley value of 0.93Ω at annealing 12s.