Revisiting the Vertical Superjunction in SiGe HBT Performance Optimization

IEEE Transactions on Electron Devices, vol. 72, pp. 1523–1527

Abstract

We numerically investigate a new asymmetric superjunction (SJ) collector profile implemented in the context of high-speed 90-nm silicon-germanium heterojunction bipolar transistors (SiGe HBTs). After reviewing past results on vertical SJ SiGe HBT collector design, we present a new SJ profile, which was generated using Bayesian optimization techniques. This new design provides improvements over both a standard collector profile and a standard SJ profile. The new profile provides a substantial increase in maximum cutoff frequency (${f}_{T}$), with a slight increase in open-base-collector–emitter breakdown voltage ($\text {BV}_{\text {CEO}}$). Then, we demonstrate, via hydrodynamic (HD) simulations and numerically solving the Boltzmann transport equation (BTE), that the simulated results are physically grounded. Finally, we address control and manufacturing concerns.

Authors 4

1. Justin P. Heimerl

   Georgia Institute of Technology

   Affiliation as printed

   School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA, USA

2. Harrison P. Lee

   Georgia Institute of Technology

   Affiliation as printed

   School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA, USA

3. Christoph Jungemann Aachen Chair of Electromagnetic Theory

   RWTH Aachen University

   Affiliation as printed

   Chair of Electromagnetic Theory, RWTH Aachen University, Aachen, Germany

4. John D. Cressler

   Georgia Institute of Technology

   Affiliation as printed

   School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA, USA