Design of composite channels for optimized transport in nitride devices

Abstract

Heterostructure field effect transistors (HFETs) based on AlGaN / GaN structures have shown good performance as high power and high frequency devices. Theoretical simulations of transport in short channel HFETs show that there are several areas where considerable improvements in mobility, etc. can be made if thin composite structures (as considered in this work) can be utilized. We examine transport in a metal / AlGaN / InN / GaN composite structure. The InN region is very thin (∼ 15 Å) and is introduced to improve the low field transport without significantly impacting the device breakdown properties. Our model is capable of examining any other type of composite structure as well. Our simulation method consists of charge control solution of the heterostructure wave functions, followed by Monte Carlo simulation of scattering and free flight events. We present comparison of results on i) metal / AlGaN / GaN structure, and ii) a metal / AlGaN / GaN structure with a thin InN channel of the order of a few mono-layers. We find that mobility in the channel can improve considerably with very little effect on the mobility - charge product. Indeed, the charge density induced in the thin InN channel region is ∼ 1013cm2. While the peak velocities in a metal / AlGaN / InN / GaN structure exhibit an increase of nearly 30% over the values in metal / AlGaN / GaN structures, the low field mobilities are also increased. Low-field mobilities of ∼ 2500 cm2 (V · s)∼ are predicted along with high sheet charges for low interface disorder for the structure with a thin InN layer. For higher degree of interface disorder (∼ 70Å), we have found good agreement with experimental Hall mobility data for similar structures. At higher electric fields, we find that most electron population transfers to higher valleys or other sub-bands that lie in AlGaN or GaN. This ensures that high field breakdown of low band gap InN layer is also suppressed.

This is a preview of subscription content, access via your institution.

We’re sorry, something doesn't seem to be working properly.

Please try refreshing the page. If that doesn't work, please contact support so we can address the problem.

References

  1. [1]

    V. Y. Davydov, A. A. Klochikhin, R. P. Seisyan, V. V. Emstev, S. V. Ivanov, F. Bechstedt, J. Furthmüller, H. Harima, A. V. Mudryi, J. Aderhold, O. Smechinova, and J. Graul, Phys. Status Solidi B 229, R1 (2002).

    CAS  Article  Google Scholar 

  2. [2]

    V. Y. Davydov, A. A. Klochikhin, V. V. Emtsev, S. V. Ivanov, V. V. Vekshin, F. Bechstedt, J. Furthmüller, H. Harima, A. V. Murdyi, A. Hashimoto, A. Yamamoto, J. Aderhold, J. Graul, and E. E. Haller, Phys. Status Solidi B 230, R4 (2002).

    CAS  Article  Google Scholar 

  3. [3]

    J. Wu, W. Walukiewicz, K. M. Yu, E. E. J. W. A. Haller III, H. Lu, W. J. Schaff, Y. Saito, and Y. Nanishi, Appl. Phys. Lett. 80, 3967 (2002).

    CAS  Article  Google Scholar 

  4. [4]

    B. E. Foutz, S. K. O'Leary, M. S. Shur, and L. F. Eastman, J. Appl. Phys. 85, 7727 (1999).

    CAS  Article  Google Scholar 

  5. [5]

    K. Yokoyama and K. Hess, Phys. Rev. B 33, 5595 (1986).

    CAS  Article  Google Scholar 

  6. [6]

    R. F. Davis, A. M. Roskowski, E. A. Preble, J. S. Speck, B. Heying, J. A. Glaser Jr, E. R. Freitas, and W. E. Carlos, Proc. IEEE 90, 993 (2002).

    CAS  Article  Google Scholar 

  7. [7]

    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, and J. Hilsenbeck, J. Appl. Phys. 85, 3222 (1999).

    CAS  Article  Google Scholar 

  8. [8]

    M. Singh, Y. Zhang, J. Singh, and U. Mishra, Appl. Phys. Lett. 77, 1867 (2000).

    CAS  Article  Google Scholar 

  9. [9]

    M. Singh and J. Singh, J. Appl. Phys. 94, 2498 (2003).

    CAS  Article  Google Scholar 

  10. [10]

    V. W. L. Chin, T. L. Tansley, and T. Osotchan, J. Appl. Phys. 75, 7365 (1994).

    CAS  Article  Google Scholar 

  11. [11]

    R. R. Reeber and K. Wang, MRS Internet J. Nitride Semicond. Res. 6, 1 (2001).

    Article  Google Scholar 

  12. [12]

    I. Vurgaftman, J. R. Meyer, and L. R. Ram-Mohan, J. Appl. Phys. 89, 5815 (2001).

    CAS  Article  Google Scholar 

  13. [13]

    J. A. Majewski, G. Zandler, and P. Vogl, J. Phys.: Condens. Matter 14, 3511 (2002).

    CAS  Google Scholar 

  14. [14]

    E. O. Kane, J. Phys. Chem. Solids 8, 38 (1959).

    CAS  Article  Google Scholar 

  15. [15]

    A. T. Meney, E. P. O'Reilly, and A. R. Adams, Semicond. Sci. Tech. 11, 897 (1996).

    CAS  Article  Google Scholar 

  16. [16]

    I. P. Smorchkova, C. R. Elsass, J. P. Ibbetson, R. Ventury, B. Heying, P. Fini, E. Haus, S. P. DenBaars, J. S. Speck, and U. K. Mishra, J. Appl. Phys. 86, 4520 (1999).

    CAS  Article  Google Scholar 

  17. [17]

    T. L. Tansley and C. P. Foley, Electronics Lett. 20, 1066 (1984).

    CAS  Article  Google Scholar 

  18. [18]

    A. Yamamoto, T. Shin-ya, T. Sugiura, and A. Hashimoto, J. Cryst. Growth 189/190, 461 (1998).

    Article  Google Scholar 

  19. [19]

    K. Seeger, Semiconductor Physics - An Introduction (Springer-Verlag, 1999).

    Google Scholar 

Download references

Acknowledgments

This work was supported by grants F001681 (the POLARIS program) and F004815 from the U. S. Office of Naval Research.

Author information

Affiliations

Authors

Corresponding author

Correspondence to Madhusudan Singh.

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Singh, M., Singh, J. & Mishra, U.K. Design of composite channels for optimized transport in nitride devices. MRS Online Proceedings Library 798, 713–718 (2003). https://doi.org/10.1557/PROC-798-Y7.9

Download citation