AVS 49th International Symposium
    Electronic Materials and Devices Wednesday Sessions
       Session EL+SC-WeP

Paper EL+SC-WeP4
Design and Simulation of AlGaN/GaN Heterojunction Bipolar Transistors

Wednesday, November 6, 2002, 11:00 am, Room Exhibit Hall B2

Session: Poster Session
Presenter: K.P. Lee, University of Florida
Authors: K.P. Lee, University of Florida
S.J. Pearton, University of Florida
F. Ren, University of Florida
J.-I. Chyi, National Central University, Taiwan
A. Dabiran, SVT Associates
P.P. Chow, SVT Associates
Correspondent: Click to Email
The progress in developing AlGaN/GaN HBTs has been very limited compared to HEMT devices in the same materials system.HBTs would have advantages of better linearity,higher output power,better radiation resistance and more uniform threshold voltage compared to field effect transistors.To date,dc current gains in HBTs have been limited to <30 at room temperature and the rf performance is poor.The high base resistance is one of the limiting factors in npn structures.We have used a drift-diffusion model to simulate the dc characteristics of a variety of structures designed to improve the HBT performance.These include a superlattice base to enhance the hole concentration due to incomplete ionization of the Mg acceptors,base grading and a regrown base contact structure.The anisotropy in transport properties of the superlattice base have been taken into account.Base transport enhancement is predicted by the introduction of a quasi-electric field in the base layer.The minority carrier lifetime in the base is also a critical parameter determining the HBT performance.A comparison will be given of the relative strengths of the different device structures and their prospects for realizing a high gain,high speed,robust AlGaN/GaN HBT technology.