Title:
Device Layout Techniques for RF Performance Enhancement on SiGe HBTs for Future Generation BiCMOS Technology
Device Layout Techniques for RF Performance Enhancement on SiGe HBTs for Future Generation BiCMOS Technology
Author(s)
Sepulveda, Nelson E.
Advisor(s)
Cressler, John D.
Ghalichechian, Nima
Ansari, Azadeh
Ghalichechian, Nima
Ansari, Azadeh
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Abstract
A study of RF performance techniques and their tradeoffs for SiGe heterojunction transistor (HBT) devices was presented. Performance results metrics showed that the τTH can be reduced by up to 37%, with increased fmax (by 17%), increased 1dB compression point (P1dB) (by 9%), and higher power-added-efficiency (PAE) (by 1.3%), and increased transducer gain (by 4.7%) using only layout optimization, with only a slight degradation of 4.5% in maximum available gain (MAG), and 8% in fT. The candidate device layouts presented can assist circuit designers in mitigating thermal memory effects at the device level, thereby improving the overall linearity of power amplifiers. This work has been accepted for publication and is available online on IEEE Transactions on Electron Devices.
Similarly, another technique using induced stress to engineer the bandgap and improve performance was presented. The results show that adding more dummy metal layers to the BEOL increases collector current density (JC) and base current density (JB) at most by 25% and 15%, respectively. Similarly, additional dummy metal layers reduce current gain (β) and JB stress degradation by 30% and 100%, respectively. Sentaurus TCAD was used to explain how reduced self-heating contributes more strongly to the Auger generation rate than the stress-induced bandgap modulation, thereby improving reliability. This work has been accepted for publication and presented at the IEEE BiCMOS and Compound Semiconductor Integrated Circuits and Technology Symposium.
Future work should be focused on how these performance enhancements will be impacted by the RF breakdown due to BEOL dummy layers. In addition, another unexplored aspect of reliability using BEOL dummy metal layers as a performance enhancement technique is operation over a wide range of temperatures and its related physics.
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Date Issued
2023-04-05
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Resource Type
Text
Resource Subtype
Dissertation