Thermal stability in RF transistors has been one of the major issue for the reliabilty of Power amplifier. A novel base ballasting scheme for interdigitated power RF bipolar transistors has demonstrated improved performance and thermal stability. The nonlinear ballast resistor in series with each base finger is implemented by depletion-mode FET, which requires only minor modification in the fabrication process. Mixed mode simulation, instead of analytical equations, is used for more universal device analysis.

Progress:

Analysis efforts are now primarily focused on single device RF effects. New ballasting scheme for Power Device was demonstrated using TCAD (mixed-mode simulation) at BCTM, 97.

Publications & Presentations this Quarter:

J. Jang, E. C. Kan, R. W. Dutton and T. Arnborg, "Improved Performance and Thermal Stability of Interdigitated Power RF Bipolar Transistors with Nonlinear Base Ballasting," 1997 BCTM Conf., Sept. 1997.

Trips:

Jaejune went on a SPIE (Student-Partner Information Exchange Program) trip to Philips (Eindhoven) and Ericsson (Sweden), Sept. 1997. He also attended the 1997 BCTM Conference on Sept. 28-30 where he presented a paper.