Comprehensive study of random telegraph noise in base and collector of advanced SiGe HBT: Bias, geometry and trap locations

In this paper, we present extensive random telegraph signal (RTS) noise characterization in advanced SiGe:C heterojunction bipolar transistors. In frequency domain, in addition to 1/f noise, generation-recombination (G-R) mechanisms are observed at low base bias in the base noise. Their existence is confirmed by RTS noise measurements in time domain. The RTS amplitude evolves rather slowly with bias, indicating their mechanism to have originated in peripheral locations. In the collector side, on the onset of high-current effects, distinct RTS noise is observed that possibly originates from the traps in the trench regions. Extraction of time constants from RTS noise and their bias dependence are presented that provides estimation of trap location within the device structure.