Microwave Noise Properties of Heterojunction Bipolar Transistors

The broadband noise performance of silicon germanium (SiGe) and compound semiconductor (CS) heterojunction bipolar transistors (HBTs) is presented. The key noise mechanisms in HBTs are summarized to provide a framework through which the noise limitations of the devices can be understood. Process related details and transport physics of each class of device are then compared and contrasted with a focus on details relevant to the broadband noise performance. Fundamental noise performance limitations are presented for exemplary InP/InGaAs/InP BiCMOS DHBTs and SiGe HBTs. The state-of-the-art for SiGe and CS HBTs operating in the 1300 GHz frequency range is reviewed and interpreted in the context of fundamental performance limitations. Finally, the paper concludes with a discussion of how the performance of future HBT technology generations should improve.