Josef Boeck

Evaluation and Modeling of Voltage Stress-Induced Hot Carrier Effects in High-Speed SiGe HBTs

Hot-carrier degradation analysis and modeling of 240/380 GHz fT/fMAX SiGe HBTs are addressed. A proper stress bias setup is proposed, suitable for the evaluation of RF performance during stress interruption. The impact of stress conditions, lateral scaling and device layout is discussed. An analytical model is proposed, which predicts base current degradation, including its dependence upon stress voltage, stress duration, and emitter geometry, and contributes to understand the physical background of the phenomena.

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.

Random telegraph noise in SiGe HBTs: Reliability analysis close to SOA limit

Abstract In this paper, we present extensive random telegraph signal (RTS) noise characterization in SiGe heterojunction bipolar transistors. RTS noise, observed at the base, originates at the emitter periphery while at the collector side distinct RTS noise is observed at high-injection that originates from the traps in the shallow trench regions. Time constants extracted from RTS during aging tests allow understanding of trap dynamics and new defect formation within the device structure. This paper provides the first demonstration of RTS measurements during accelerated aging tests to study and understand generation of defects under bias stress in SiGe HBTs operating at the limit of their safe-operating area.