基于有限元法对发射极指分段结构的多指SiGe HBT的研究

针对传统多指SiGe HBT发射极指中心区域和器件中心区域温度较高导致热不稳定问题,提出了新型发射极指分段结构来抑制功率SiGe HBT中心区域的自热效应,提高器件温度分布均匀性.利用有限元软件ANSYS对器件进行建模和三维热模拟,研究器件温度分布的改善情况.结果表明,与传统不分段结构的器件相比,新型分段结构的多指SiGe HBT的指上的温度分布更加均匀、不同指上的温差和集电结结温明显降低,自热效应得到有效抑制,器件的热稳定性得到增强.

Research on Multi-finger SiGe HBT with Emitter Segmented Structure Based on Finite Element Method

In order to improve thermal instability caused by higher temperature at center of emitter and center region of device in traditional multi-finger SiGe HBTs, novel emitter segmented structures are proposed to inhibit self-heating effect in center region of device and each finger, and improve temperature distribution uniformity. The finite element method (FEM) software ANSYS is employed to model device and simulate thermal distribution so as to obtain temperature improvement. The results indicate that the temperature distribution on each finger, the temperature difference among fingers and the collector junction temperature of the HBTs with novel emitter segmented structure are improve effectively compared with the HBTs with traditional non-segmented structure. So the self-heating effect is inhibited and thermal stability is enhanced.