铝铜合金对LED芯片电极可靠性的影响

Effects of Al-Cu Alloys on the Reliability of LED Chip Electrodes

发光二极管（LED）芯片反射电极中铝的稳定性对芯片的可靠性至关重要,少量铜的加入可改善铝的耐电流性。理论计算了电子束蒸镀沉积时,镀源和镀膜中铜质量分数的对应关系。对纯铝和不同铜质量分数的铝铜合金进行了金属线耐电流测试和薄膜反射率测试,并对纯铝或铝铜合金电极的LED芯片进行了老化测试。结果表明,相对于纯铝电极结构,铜质量分数为2%的铝铜合金电极在几乎不影响反射率的前提下,可显著提高电极的耐电流性能。以铝铜合金为电极的LED芯片在老化过程中,可有效阻止铝的电迁移,从而显著提升了LED芯片的可靠性。

The stability of Al in light-emitting diodes（ LEDs） reflective electrodes plays an important role in the reliability of chips. The addition of a small amount of Cu to Al can improve the current tolerance of Al. The correspondence relation between the Cu mass fractions in evaporation source and deposited film was theoretically calculated during electron beam evaporation. The metal wire current tolerance tests and film reflectivity tests were carried out on the pure Al and Al-Cu alloys with different Cu mass fractions. And the aging tests were also performed on LED chips with pure Al and Al-Cu alloy electrodes. The results indicate that compared with the pure Al electrode structure,the Al-Cu alloy electrode with the Cu mass fraction of 2% can significantly enhance the current tolerance of the electrode,hardly affecting the reflectivity. The LED chips with Al-Cu alloy electrodes can effectively prevent the electromigration of Al during the aging process,thus greatly improving the reliability of LED chips.