In this paper hot carrier related aging of n-p-n bipolar transistors is investigated experimentally and theoretically to bring physical insight into the bipolar transistor hFE (common emitter current gain) degradation. Electrical stress experiments are performed on transistors with different base doping profiles at varying temperatures. Detailed process simulations are performed to determine the doping profiles of the base-emitter junction. Monte Carlo transport simulations are then performed at different temperatures and bias conditions to determine the electron and hole distribution functions in the baseemitter junction. AT&T’s 0.8 μ.m BICMOS technology is used to fabricate the experimental bipolar transistor structures. For this non-self aligned technology we attribute hFE degradation to the presence of hot holes and secondary electrons which are generated by hot hole impact ionization. This feed-back due to impact ionization has a dominant effect on the high energy tails of the distribution of both holes and electrons even when the overall current multiplication is low. Simple hot electron energy transport models do not contain the complexity to properly describe ionization feedback and carrier heating, and are therefore inadequate. An exponential dependence of the transistor lifetime on BVEBO is deduced for constant voltage stress (Vstress < BVEBO) conditions, confirming the importance of secondaries in the process of degradation.
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D.R. Collins, Appl. Phys. Lett., 13, 264 (1968).
D.R. Collins, IEEE Trans. Electron Devices, 16, 403 (1969).
B.A. McDonald, IEEE Trans. Electron Devices, 17, 871 (1970).
S.P. Joshi, R. Lahri, and C. Lage, IEDM Tech. Digest, 182 (1987).
D.D. Tang and E. Hackbarth, IEEE Trans. Electron Devices, 35, 2101 (1988).
J.D. Burnett and C. Hu, IEEE Trans. Electron Devices, 35, 2238 (1988).
D. Burnett and C. Hu, Proc. IEEE International Reliability Symposium, 164 (1990).
C.J. Huang, T.A. Grotjohn, D.K. Reinhard, and C.J. Sun, IEEE Proc. Bipolar Circuits and Technology Meeting, 134, (1992).
D. Burnett, T. Horiuchi, and C. Hu, IEDM Tech. Digest, 181 (1990).
M.S. Tyagi, Solid State Electron., 11, 99 (1968).
I. Getreu, Modeling the Bipolar Transistor, Beaverton, Oregon : Tektronics Inc., 1976.
J.D. Burnett and C. Hu, IEEE Trans. Electron Devices, 37, 1171 (1990).
M. Cohen, T. K. Bergstresser, Phys. Rev, 141, 789 (1965).
H. Shichijo, J. Y. Tang, J. Bude, D. Yoder, in Monte Carlo device simulation: full band and beyond, pp. 285–307, edited by K. Hess, Kluwer Academic Publishers, Boston, 1991.
J. Bude, G. J. Iafrate, K. Hess, Phys. Rev. B, 45, 10958, (1992).
J. Bude, K. Hess, J. Appl. Phys. 72, 3554 (1992).
P. Habas, A. Lugbauer, S. Selberherr, in Workshop on Numerical Modeling of Process and Devices for Integrated Circuits: NUPAD IV edited by M. Law, A. Strojwas, 135 (1992).
S. M. Sze, Physics of Semiconductor Devices, p. 15, John Wiley & Sons, New York, 1981.
E. O. Kane, “Zener tunneling in semiconductors,” Journal Phys. Chem. Solids, 12,181 (1959).
G. A. M. Hurkx, “On the modeling of tunneling currents in reverse-biased P-N junctions,” Solid-State Electron., 32, 665 (1989).
I.C. Kizilyalli and J.D. Bude, IEEE Trans. Electron Devices, 41,1083 (1994).
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Kizilyalli, I.C., Bude, J.D. Hot Carrier Degradation of Gain in Bipolar Transistors. MRS Online Proceedings Library 391, 11 (1995). https://doi.org/10.1557/PROC-391-11