Effect of 60Co ray radiation on electrical properties of SiGe HBTs at low temperatures

In this article, total ionizing dose (TID) irradiation experiments were carried out on germanium-silicon heterojunction bipolar transistors (SiGe HBTs) under different bias and temperature conditions. The electrical performance and noise characteristics of the device were characterized before and after irradiation using a semiconductor parameter analyzer and a 1/f noise test system, respectively. The variation of radiation sensitivity parameters with the TID effect and temperature of the device was obtained, and the mechanism of radiation damage degradation was also identified. Results suggest that the oxide-trap charges and interface states induced by irradiation are the main causes for SiGe HBT electrical parameters degradation. With the decreased temperature, Gummel characteristics and 1/f noise are significantly improved. It's found that oxide-trap charges and interface states generated at 93 K is less than that at 300 K. This work lays the foundation for the application of SiGe HBT in aerospace area.