栅极导电层Au迁移导致放大器失效原因分析

针对限幅低噪声放大器使用过程中出现输出不稳定现象,利用扫描电镜和能谱仪对场效应管栅极表面的金属缺失层和栅源之间的金属堆积物进行微观分析,寻找放大器工作不正常的原因。结果表明:场效应管栅极Au层的电迁移,使导线局部电阻增大,温度升高,导致Au的热迁移加重,引起导线出现孔洞和栅源中间堆积金属颗粒,使栅极导线出现开路和栅源极间产生不稳定接触,最终导致场效应管的工作参数漂移和放大器工作不正常。

Failure analysis of amplifier by Au electromigration on conducting layer of the gate

Aimed at the problem of output unstable of the limiting low noise amplifier(Amp) under the work,the microstructures of components of the metal layer that on the surface of MESFET which in the limiting low noise Amp were studied with SEM and EDS,and found the failure reasons of the Amp.Results show that the gold electric migration on the grid of MESFET causes the Au conductive layer resistance and temperature increase,and Au heat migration is heavy,which make metal particles between the gate and the source are stacked,which causes the gate wire off and unstable contact between the gate and the source,that causes MESFET parameters drift and lead to the amplifier output unstable.