75-GHz fT SiGe-Base Heterojunction Bipolar Transistors

Gary L. Patton, James H. Comfort, Bernard S. Meyerson, Emmanuel F. Crabbé, Gerald J. Scilla, Edouard De Frésart, Johannes M.C. Stork, Jack Y.C. Sun, David L. Harame, Joachim N. Burghartz

Research output: Contribution to journalArticlepeer-review

384 Scopus citations


We report the fabrication of silicon heterojunction bipolar transistors which have a record unity-current-gain cutoff frequency (fT) of 75 GHz for a collector-base bias of 1 V, an intrinsic base sheet resistance (Rbi) of 17 kΩ/∧, and an emitter width of 0.9 µm. This performance level, which represents almost a factor of 2 increase in the speed of a Si bipolar transistor, was achieved in a poly-emitter bipolar process by using SiGe for the base material. The germanium was graded in the 45-nm base to create a drift field of approximately 20 kV/cm, resulting in an intrinsic transit time of only 1.9 ps.

Original languageEnglish
Pages (from-to)171-173
Number of pages3
JournalIEEE Electron Device Letters
Issue number4
StatePublished - Apr 1990

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