Title:  Towards a Universal Hot Carrier Degradation Model for SiGe HBTs Subjected to Electrical Stress

Committee:

Dr. John Cressler, ECE, Chair , Advisor

Dr. Shyh-Chiang Shen, ECE

Dr. Asif Khan, ECE

Dr. Nelson Lourenco, ECE

Dr. Dragomir Davidovic, Physics

Abstract:

The objective of this work is to develop a generalizable understanding of the degradation mechanisms present in complementary (NPN + PNP) Silicon-Germanium (SiGe) heterojunction bipolar transistors (HBTs) that can be used to not only predict the reliable lifetime of these devices, but also overcome some of these aging limitations using clever device engineering.  This broad motivation for understanding and improving SiGe HBT device reliability is explored through the following specific goals: 1) develop an understanding of the dominant hot carrier degradation sources across temperature (25 K – 573 K) ; 2) develop a broad understanding of all potentially vulnerable regions of damage within a SiGe HBT using electrically measured data, and how these degradations can be captured in a modeling framework; and 3) design optimized SiGe HBTs that can potentially overcome some of these device-level limitations in reliability across temperature. Being able to simulate the electrical degradation of a complex circuit with SiGe HBTs swinging dynamically on the output plane using a universal physics-based aging model is invaluable for any circuit designer optimizing for high performance and reliability.