静电对GaN基高压LED特性的影响

Effects of Electrostatic-Discharge on GaN-Based High Voltage Light-Emitting Diode

对GaN基绿光高压LED分别施加-500、-1 000、-2 000、-3 000、-4 000、-5 000和-6 000V的反向人体模式静电打击,每次静电打击后,测量样品的I-V特性曲线及光通量等参量,研究静电打击对GaN基高压LED器件性能的影响.结果表明:当样品经过-500,-1 000、-2 000、-3 000和-4 000V的静电打击后,由于LED器件内部产生了缺陷,发生了软击穿并且反向漏电流明显增加,但光通量的变化不明显;当经过-5 000V和-6 000V的静电打击后,由于发生了热模式击穿,温度迅速升高,在结区形成熔融通道,使LED的光通量明显减小,甚至衰减到未打击时的一半;在经受-6 000V的静电打击后,正向电压的减小和反向漏电流的增加更加明显,漏电现象更加明显,严重影响了器件的性能,最终使LED样品失效.

GaN-based high-voltage green light-emitting diodes were biased by negative Human-Body-Mode electrostatic discharge （ESD） with --500,--1 000,--2 000,--3 000,--4 000,--5 000 and --6 000 V. The I-V characteristic and luminous flux under different electrostatic shock voltages were comparative analyzed after each shock. The results show that the LED has a soft breakdown which accompanied with apparent increased reverse leakage current and unapparent luminous flux change , which due to the generation of defect after ESD stressing at -- 500, -- 1 000, -- 2 000, -- 3 000 and -- 4 000V~ When the device was biased to --5 000 V and --6 000 V,a sharp decrease of luminous flux appears,even decay to 50% of light output than before stressing. And forward voltage and reverse leakage current show a large degree of decrease and increase respectively after ESD shock of-6000V, which is due to the thermal model breakdown at this moment. The thermal model breakdown make temperature rise rapidly and form a melting channel, which disabled the LED eventually.