High-frequency characteristic optimization of heterojunction bipolar transistors

Yi-Ming Li*, Ying Chieh Chen, Chih Hong Hwang

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

Abstract

With the downward scaling of IC critical dimension, the speed of SiGe heterqjunction bipolar transistors has been increased dramatically. The speed of HBTs is dominated by the base transit time, which may be strongly influenced by the doping profile in the base region and the Ge concentration of base region. Therefore, the determination of the doping profile and Ge concentration of base region is crucial for design of SiGe HBTs in advanced communication circuits. In this study, the design of HBTs is transformed to a convex optimization problem, and solved efficiently by geometric programming approach. The result shows that a 23% Ge fraction may maximize the current gain and a 12.5% Ge can maximize the cut-off frequency, where 254 GHz is achieved. The accuracy of the optimization technique was confirmed by TCAD simulation. This study successfully transforms the device characteristic and manufacturing limitation into a geometric programming model and provides an insight into design of SiGe HBTs.

Original languageEnglish
Title of host publicationTechnical Proceedings of the 2008 NSTI Nanotechnology Conference and Trade Show, NSTI-Nanotech, Nanotechnology 2008
Pages615-618
Number of pages4
StatePublished - 2008
Event2008 NSTI Nanotechnology Conference and Trade Show, NSTI Nanotech 2008 Joint Meeting, Nanotechnology 2008 - Quebec City, QC, United States
Duration: 1 Jun 20085 Jun 2008

Publication series

NameTechnical Proceedings of the 2008 NSTI Nanotechnology Conference and Trade Show, NSTI-Nanotech, Nanotechnology 2008
Volume3

Conference

Conference2008 NSTI Nanotechnology Conference and Trade Show, NSTI Nanotech 2008 Joint Meeting, Nanotechnology 2008
CountryUnited States
CityQuebec City, QC
Period1/06/085/06/08

Keywords

  • Bipolar transistors
  • HBT
  • High frequency
  • Impurity doping
  • Optimization
  • SiGe

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