钝化层对高压蒸汽试验中器件参数漂移的影响

Effect of Passivation on the Parameters Drift of the Devices in High-pressure Steam Experiments

采用Si02钝化层的塑封双极晶体管在EIA／JESD22-A102-C规定的121℃、100％RH、29．7 psi压力的条件试验96 h后，直流增益HFE测试值会有明显的下降，击穿电压BVCEO会略有上升。分析表明高压水汽可以穿透封装和钝化层，造成芯片内部微缺陷增加，导致器件HFE下降，BVCEO略有上升。通过优化钝化层工艺并对比试验验证，采用SiO2加Si。N4的复合钝化层，可以避免器件参数漂移，改善器件抗潮湿性能。

After the experimentation of 96 hours in the condition of 121 ℃, 100% RH and 29.7 psi pressure which prescribed in EIA/JESD22-A102-C, the HFE of plastic encapsulated bipolar devices with SiO2 passivation will decrease obviously, and BVCEO will increase a little. It is approved by theoretical analysis that High-pressure steam can penetrate through encapsulation and passivation and induce increase of micro-defects which can result in descending of HFE and increase of BVCEO. Through contrast of passivation process optimization experimentation, it is proved that the parameters drift of the devices with SiO2 and Si3N4 recombination passivation can be avoided, and the ability of anti- humidity can be improved.