Low frequency noise temperature measurements in SiGe:C heterojunction bipolar transistors

In this work, we present LFNoise measurements versus temperature (120 K-295 K) in SiGe:C HBTs issued from a 0.13 μm BiCMOS technology supplied by STMicroelectronics. For this temperature range (120 K-295 K) on TO box mounted transistors are used. The base current spectral density, S_IB, is directly measured using a low noise current amplifier base setup measurement. All the tested transistors showed steady 1/f noise level for temperatures higher than 160 K. Below 220-240 K, generation-recombination (g-r) components appeared and increased more and more with the decrease of the temperature. Concerning the g-r components, two behaviors were observed at very low temperature. It must be noticed that, for the tested transistors, no RTS signature was observed in the time domain, except at very low temperature where a very small RTS amplitude was observed for a few transistors.