Abstract
Gallium nitride (GaN) based transistors are advantageous for high voltage power switching applications due to its superior material properties. In power switching applications normally-off transistors are preferred for their fail-safe operation at high voltages in addition to the advantages of lower power consumption and simpler drive circuits. However, planar AlGaN/GaN high-electron mobility transistors (HEMTs) are normally-on devices with negative threshold voltage due to the presence of polarization induced two-dimensional electron gas (2DEG) at the heterojunction at zero gate voltage. It has been experimentally observed that a normally-on AlGaN/GaN FinFET can be transformed into a normally-off transistor with positive threshold voltage by reducing the fin width. In this paper a physics based analytical model for the threshold voltage of a AlGaN/GaN FinFET is presented. It is seen that the strain induced in the channel region in the piezoelectric GaN layer just below the heterojunction plays an important role in determining the threshold voltage at narrow fin widths.
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References
E. Ture, P. Brukner, B.-J. Godejohann, R. Aidam, M. Alsharef, R. Granzner, F. Schwierz, R. Quay, O. Ambacher, High-current submicrometer tri-gate GaN high-electron mobility transistors with binary and quaternary barriers. J. Electron Devices Soc. 4(1) (2016)
K. Ohi, T. Hashizume, Drain current stability and controllability of threshold voltage and subthreshold current in a multi-mesa-channel AlGaN/GaN high electron mobility transistor. Jpn. J. Appl. Phys. 48, 1–5 (2009)
K. Ohi, J.T. Asubar, K. Nishiguchi, T. Hashizume, Current stability in multi-mesa-channel AlGaN/GaN HEMTs. IEEE Trans. Electron Devices 60, 2997–3004 (2013)
M.A. Alsharef, R. Granzner, F. Schwierz, Theoretical investigation of trigate AlGaN/GaN HEMTs. IEEE Trans. Electron Devices 60, 3335–3341 (2013)
G. Steude, B.K. Meyer, A. Goldner, A. Hoffmann, A. Kaschner, F. Bechstedt, H. Amano, I. Akasaki, Strain modification of GaN in AlGaN/GaN epitaxial films. Jpn. J. Appl. Phys. 38, 498–500 (1999)
B. Jogai, J.D. Albrecht, E. Pan, Effect of electromechanical coupling on the strain in AlGaN/GaN heterojunction field effect transistors. J. Appl. Phys. 94, 3984–3989 (2003)
B. Jogai, Free electron distribution in AlGaN/GaN heterojunction field-effect transistors. J. Appl. Phys. 91, 3721–3729 (2002)
O. Ambacher, J. Smart, J.R. Shealy, N.G. Weimann, K. Chu, M. Murphy, W.J. Schaff, L.F. Eastman, R. Dimitrov, L. Wittmer, M. Stutzmann, W. Rieger, J. Hilsenbeck, Two-dimensional electron gases induced by spontaneous and piezoelectric polarization charges in N- and Ga-face AlGaN/GaN heterostructures. J. Appl. Phys. 85, 3222–3233 (1999)
D.J. Frank, Y. Taur, H.-S.P. Wong, Generalized scale length for two-dimensional effects in MOSFET’s. IEEE Electron Device Lett. 19, 385–387 (1998)
M. Povolotskyi, M. Auf der Maur, A. Di Carlo, Strain effects in freestanding three-dimensional nitride nanostructures. Phys. Stat. Sol. 11, 3891–3894 (2005)
R. Kern, P. Muller, Elastic relaxation of coherent epitaxial deposits. Surf. Sci. 392, 103–133 (1997)
P. Muller, R. Kern, Some aspects of coherent epitaxial deposits. Microsc. Microanal. Microstruct. 8, 229–238 (1997)
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Ghatak, P., Dutta, D., Bhat, N. (2019). A Physics Based Analytical Model for the Threshold Voltage of a Normally-off AlGaN/GaN FinFET. In: Sharma, R., Rawal, D. (eds) The Physics of Semiconductor Devices. IWPSD 2017. Springer Proceedings in Physics, vol 215. Springer, Cham. https://doi.org/10.1007/978-3-319-97604-4_32
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DOI: https://doi.org/10.1007/978-3-319-97604-4_32
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