基区Ge组分分布对SiGe HBT热学特性的影响

Effects of Ge-Profile on Thermal Characteristics of SiGe HBT

建立了SiGe HBT热电反馈模型,对基区Ge组分矩形分布、三角形分布和梯形分布的SiGe HBT的热特性进行研究。结果表明,在Ge总量一定的前提下,Ge组分为三角形和梯形分布结构的SiGe HBT峰值温度较低、温差较小,温度分布的均匀性优于Ge组分矩形分布结构的SiGeHBT,具有更好的热特性。对不同Ge组分分布下器件增益与温度的依赖关系进行研究,发现当基区Ge组分为三角形和梯形分布时,随着温度升高,器件增益始终低于Ge组分矩形分布的器件,且增益变化较小,提高了器件的热学和电学稳定性,扩大了器件的应用范围。

An electro-thermal feedback model was established,and effects of different Ge-profiles,such as box,triangular and trapezoidal Ge-profiles,on SiGe HBT thermal characteristics were investigated.Results showed that,for the same Ge amount,SiGe HBT with triangular and trapezoidal Ge-profiles had a lower peak temperature and smaller temperature difference than SiGe HBT with box Ge-profile,which indicated better thermal characteristics.Dependency of current gain β on temperature for different Ge profiles was studied,and it was found that SiGe HBT with triangular and trapezoidal Ge-profiles had a smaller β than SiGe HBT with box-profile and had less change with rising temperature,hence an enhanced thermal and electric stability and extended applications for SiGe HBTs.