由栅氧损伤引起闩锁效应的失效分析

Failure Analysis on the Latch-up Effect Caused by the Gate Oxide Damage

随着MOS器件特征尺寸的缩小和栅氧化层厚度的减薄,栅氧损伤成为MOS集成电路在实际应用中的主要失效模式之一。闩锁是CMOS集成电路结构所固有的寄生效应,寄生的可控硅结构一旦被特定条件触发,会在电源与地之间形成大电流通路,导致整个器件失效。对一例由栅氧损伤引起器件闩锁效应的失效进行分析。通过微光显微镜(EMMI)技术和激光诱导阻值变化(OBIRCH)技术进行失效定位,在电路板级通信状态下进行闩锁效应复现及验证。最后通过分析损伤所在的电路功能和器件结构,阐述闩锁效应形成的机理。

With the decreasing feature dimension in MOS devices and the thickness peduction of the gate oxide, the gate oxide damage becomes one of the main failure modes of MOS integrated circuits in application. Latch-up is a parasitic effect of CMOS circuits in practical application. Once the parasitic silicon controlled rectifier （SCR） structure is triggered, a high current from the power supply to the ground is generated, which makes the device invalidation. The latch-up effect caused by the gate oxide damage were studied. Emission microscope （EMMI） and optical beam induce resistance change （OBIRCH） were used to isolate the failure location. The latch-up effect was reproduced and validated on the communication interface board. Finally the mechanism of the latch-up effect was discussed by analy- zing the function and circuit structure of the failure location.