The large signal characteristics of Cu-gate and Ni/Au-gate AlGaN/GaN high-electron-mobility transistors (HEMTs) were compared. The tested devices were fabricated on two different parts of the same wafer following the same fabrication steps, the only difference being in the Schottky contact material. Comparison of the direct-current (DC) and radio frequency (RF) characteristics points out a critical drain current collapse in the Cu-gate devices, with detrimental effects on the RF performance, whereas the Ni/Au-gate HEMTs performed properly during DC, pulsed, and RF measurements. Investigations on the drain current transients and on the I D–V GS characteristics, obtained by pulsed signals, suggest the presence of an acceptor trap density in the AlGaN barrier, beneath the Cu Schottky gate contact, responsible for the poorer performance of the Cu-gate device; an activation energy of 430 meV was extracted. This defectivity seemed to be due to a copper diffusion event, activated by thermal stress induced in the sample during the plasma-enhanced chemical vapor deposition (PECVD) of SiN. Numerical simulations carried out on the tested structure qualitatively support the presence of a trap density explaining the nature of the observed drain current transients.
Article PDF
Similar content being viewed by others
References
U.K. Mishra, L. Shen, T.E. Kazior, and Y.-F. Wu, Proc. IEEE 96, 287 (2008).
A.C. Schmitz, A.T. Ping, M. Asif Khan, Q. Chen, J.W. Yang, and I. Adesida, J. Electron. Mater. 27, 255 (1998).
G.H. Jessen, R.C. Fitch, J.K. Gillespie, G.D. Via, N.A. Moser, M.J. Yannuzzi, A. Crespo, R.W. Dettmer, and T.J. Jenkins, Proc. IEEE GaAs Symp., Nov. 2003, pp. 277–279.
Y. Yamashita, A. Endoh, K. Ikeda, K. HikosakaL, T. Mimura, M. HigashiwakiL, T. Matsui, and S. Hiyamizu, J. Vac. Sci. Technol. B, Microel. Process. Phenom. 23, L13 (2005).
J.-P. Ao, D. Kikuta, N. Kubota, Y. Naoi, and Y. Ohno, IEEE Electron. Dev. Lett. 24, 500 (2003).
H.F. Sun, A.R. Alt, and C.R. Bolognesi, IEEE Electron. Dev. Lett. 28(5), May 2007.
L. Wang, M.I. Nathan, T.-H. Lim, M.A. Khan, and Q. Chen, Appl. Phys. Lett. 68, 1267 (1996).
R. Vetury, N.Q. Zhang, S. Keller, and U.K. Mishra, IEEE Trans. Electron. Dev. 48, 560 (2001).
Y.-F. Wu, D. Kapolnek, J. Ibbetson, N.-Q. Zhang, P. Parikh, B. Keller, and U.K. Mishra, 1999 IEDM Technical Digest, Dec. 1999, pp. 925–927.
J.R. Shealy, V. Kaper, V. Tilak, T. Prunty, J.A. Smart, B. Green, and L.F. Eastman, Condens. Matter 14, 3499 (2002).
M. Hiroshi, K. Hisao, and H. Kenji, J. Appl. Phys. 81, 7746 (1997).
E.R. Weber, Appl. Phys. A 30, 1 (1983).
A. Cros, M.O. Aboelfotoh, and K.N. Tu, J. Appl. Phys. 67, 3328 (1990).
C.-A. Chang, J. Appl. Phys. 67, 566 (1990).
P.H. Wohlbier, (Trans. Tech, OH, 1975), Vol. 10, pp. 89–91.
C.-Y. Chen, L. Chang, E.Y. Chang, S.-H. Chen, and D.-F. Chang, Appl. Phys. Lett. 77(21), Nov. 20, 2000.
D.A. MacQuistan and F. Weinberg, J. Cryst. Growth 110, 745 (1991).
R.N. Hall and J.H. Racette, J. Appl. Phys. 35, 379 (1964).
C.S. Fuller, J.M. Whelan, and J. Phys, Chem. Solids 6, 173 (1958).
Y. Furukawa, J. Phys. Chem. Solids 26, 1869 (1965).
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Esposto, M., Lecce, V.D., Bonaiuti, M. et al. The Influence of Interface States at the Schottky Junction on the Large Signal Behavior of Copper-Gate GaN HEMTs. J. Electron. Mater. 42, 15–20 (2013). https://doi.org/10.1007/s11664-012-2268-2
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s11664-012-2268-2