混合模式电应力损伤对SiGe HBT器件1/f噪声特性的影响研究

研究了混合模式应力损伤对SiGe HBT器件直流电性能的影响,对比了混合模式损伤前后器件1/f噪声特性的变化。结果表明,在SiGe HBT器件中,混合模式损伤在Si/SiO₂界面产生界面态缺陷P_b,导致小注入下基极电流增加;H原子对多晶硅晶界悬挂键的钝化作用引起中等注入区基极电流减小,导致电流增益增强。混合模式损伤缺陷位于硅禁带宽度内本征费米能级附近,虽然使基区SRH复合电流增加,却不会改变器件的低频噪声特性。

Impact Research of Mixed-Mode Stress Damages on the 1/f Noise Characteristics in SiGe HBT Devices

The effects of mixed-mode stress damage on the DC performance of SiGe HBT devices were studied, and the changes in 1/f noise characteristics of the devices before and after the mixed-mode damage were compared. It shows that the mixed mode damage produces an interfacial defect Pb at the Si/SiO₂ interface, which leads to the increase of the base current in low injection level. On the other hand, the base current in the medium injection region decreases due to the passivation of H atoms of the dangling bonds at polysilicon grain boundries, which leads to the enhancement of current gain. However, the mixed-mode damage defects are mainly located near the intrinsic Fermi level within the silicon band gap, which leads the increase of the SRH recombination component of base current. As a result, the low frequency noise characteristics of the device are not changed.