Progressive current degradation and breakdown behavior in GaN LEDs under high reverse bias stress

• 来源期刊: 中国物理B（英文版）
• 关键词: GaN LEDs current degradation breakdown behavior reverse bias stress
• 年，卷（期）: 2017,（8）
• 页码范围: 429-432
• 页数: 4页
• 语种: 英文
• DOI: 10.1088/1674-1056/26/8/087308

摘要

The progressive current degradation and breakdown behaviors of GaN-based light emitting diodes under high reversebias stress are studied by combining the electrical,optical,and surface morphology characterizations.The current features a typical "soft breakdown" behavior,which is linearly correlated to an increase of the accumulative number of electroluminescence spots.The time-to-failure for each failure site approximately obeys a Weibull distribution with slopes of about 0.67 and 4.09 at the infant and wear-out periods,respectively.After breakdown,visible craters can be observed at the device surface as a result of transient electrostatic discharge.By performing focused ion beam cuts coupled with scan electron microscope,we observed a local current shunt path in the surface layer,caused by the rapid microstructure deterioration due to significant current heating effect,consistent well with the optical beam induced resistance change observations.