激光诱导p-GaN掺杂对发光二极管性能改善的分析

采用激光诱导掺锌的方法提高了常规GaN基外延片p-GaN层的空穴浓度,并将它制备成小功率白光发光二极管(LED).对其光电性能做了详细的测量并进行了加速老化实验和分析.结果表明,与常规LED相比,经过激光诱导p-GaN层掺锌LED的光电性能获得了明显改善:正向工作电压VF从3.33V降到3.13V,串联电阻从30.27Ω降到20.27Ω,室温下衰退系数从1.68×10-4降到1.34×10-4,老化1600h后的反向漏电流从超过0.2μA降为不超过0.025μA,器件的预测寿命延长了41%.器件光电性能改善的主要原因是激光诱导掺锌使LED的p-型欧姆接触改善和热阻降低所致.

Analyses of laser-induced p-type doping of GaN in the improvement of light-emitting diodes

We increase the hole concentration of the p-CaN contact layer of the epitaxial wafer of conventional GaN-based devices by laser-induced Zn doping. Improvement of the photoelectric property of light-emitting diodes (LED) is confirmed. Compared with LED with no laser-induced doping, the forward voltage under 20 mA current is decreased from 3.33 V to 3.13 V, the series resistance is decreased from 30. 27 Ω to 20. 27Ω, and the degradation coefficient at room temperature is reduced from 1.68 × 10~(-4) to 1.34 × 10~(-4). In addition, the reverse leakage current of the LED is reduced from over 0.2μA to less than 0. 025 μA after an aging time of 1600 h by accelerated lifetime testing, and the lifetime is increased about 41%. These results are attributed to the improvement of p-type ohmic contact and the decrease of the thermal resistance due to laser-induced doping of Zn to the p-GaN contact layer.