Applied Physics A

, Volume 31, Issue 3, pp 119–138 | Cite as

ROMANS II A two-dimensional process simulator for modeling and simulation in the design of VLSI devices

  • C. D. Maldonado
Invited Paper


During the past decade considerable effort has been devoted to the development of two-dimensional (2D) device simulators while the development of two-dimensional process simulators, except for the past few years, has been almost nonexistent. To eliminate this lag in the development of 2D process simulators recent research has been directed entirely towards the development of simulators for predicting the thermal redistribution of impurities in bulk device structures; whereas, in the present paper a process simulator, ROMANS II, has been developed which is capable of simulating the redistribution of impurities in both bulk and SOS device structures. All the elements of two-dimensional process modeling which were used to assemble ROMANS II are presented. For example, Runge's approximate procedure for characterizing 2D distributions of ion implants in physical domains of actual device structures is discussed in great detail. Also discussed in great detail are the 2D empirical and phenomenological models used to specify oxide growths on silicon surfaces. A complete formulation of the governing nonlinear boundaryvalue problem for the redistribution of impurities in the physical domain of a device and the corresponding transformation of this problem to a fixed-time invariant rectangular domain by means of a translation-scaling transformation are presented. The numerical algorithm used to solve the nonlinear boundary-value problem in the fixed-time invariant rectangular domain is briefly discussed since a more detailed discussion is given elsewhere. Finally, ROMANS II is utilized to simulate the thermal redistribution of the field, channel, and source/drain implants which were used in fabricating a 1 μmn-channel enhancement mode device. The simulation was carried through the entire device fabrication schedule and the surface topography and corresponding equi-density contours for the net impurity concentration at the end of key process steps are given.




Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. 1.
    D. Barbe (ed.):Very Large Scale Integration VLSI, Springer Ser. Electrophys.5 (Springer, Berlin, Heidelberg, New York 1982)Google Scholar
  2. 2.
    E.M. Buturla, P.E. Cottrell, B.M. Grossman, K.A. Salsburg, M.B. Tawlor, C.T. McMullen: Three-Dimensional Finite Element Simulation of Semiconductor Devices; 1980 Proc. IEEE Int. Solid-State Circuits Conf. (San Francisco, CA, Feb. 1980) pp. 76–77Google Scholar
  3. 2a.
    W. Fichtner, R.L. Johnston, D.J. Rose: Three-Dimensional Numerical Modeling of Small-Size MOSFET's; presented at 39th Annual Device Research Conference (June 22–24, 1981) University of California, Santa Barbara, CAGoogle Scholar
  4. 3.
    D.A. Antoniadis, S.E. Hansen, R.W. Dutton: SUPREM II-A Program for IC Process Modeling and Simulation, TR No. 5019-2, Stanford Electronics Laboratories, Stanford University, Stanford, CA (June 1978)Google Scholar
  5. 4.
    H.G. Lee, J.D. Sansbury, R.W. Dutton, J.L. Moll: IEEE J. SC-13, 455–561 (1978)Google Scholar
  6. 5.
    J.P. Krusius, J. Nulman, J.V. Faricelli, J. Fray: IEEE Trans. ED-29, 435–444 (1982)Google Scholar
  7. 6.
    D.D. Warner, C.L. Wilson: Bell. Syst. Tech. J.59, 1–41 (1980)Google Scholar
  8. 7.
    R. Tielert: IEEE Trans. ED-27, 1479–1483 (1980)Google Scholar
  9. 8.
    H. Ryssel, K. Haberger, K. Hoffmann, G. Prinke, R. Dümcke, A. Sachs: IEEE Trans. ED-27, 1484–1492 (1980)Google Scholar
  10. 9.
    H.G. Lee: Two-Dimensional Impurity Diffusion Studies: Process Models and Test Structures for Low-Concentration Boron Diffusion; TR No. 6201-8, Stanford Electronics Laboratories, Stanford University, Stanford, CA (August 1980)Google Scholar
  11. 10.
    D.J. Chin, M.R. Kump, H.G. Lee, R.W. Dutton: IEEE Trans. ED-29, 336–340 (1982)Google Scholar
  12. 11.
    B.R. Penumalli: Process Simulation in Two-Dimensions; Proc. NASECODEII Conf. (Trinity College, Dublin, Ireland, June 1981) pp. 264–269Google Scholar
  13. 12.
    W.D. Murphy, W.F. Hall, C.D. Maldonado: Efficient Numerical Solution of Two-Dimensional Nonlinear Diffusion Equations with Non-uniformly Moving Boundaries: A Versatile Tool for VLSI Process Modeling; Proc. NASECODEII Conf. (Trinity College, Dublin, Ireland, June 1981) pp. 249–253Google Scholar
  14. 13.
    K. Taniguchi, M. Kashiwagi, H. Iwai: IEEE Trans. ED-28, 574–580 (1981)Google Scholar
  15. 14.
    D.J. Chin, M.R. Kump, R.W. Dutton: SUPRA-Stanford University PRocess Analysis program; Stanford Electronics Laboratories, Stanford University, Stanford, CA (July 1981)Google Scholar
  16. 15.
    H. Runge: Phys. Status Solidi,39a, 595–599 (1977)Google Scholar
  17. 16.
    S. Furukawa, H. Matsumura, H. Ishiwara: Jpn. J. Appl. Phys.2, 134–142 (1972)Google Scholar
  18. 17.
    B.E. Deal, A.S. Grove: J. Appl. Phys.36, 3770–3778 (1965)Google Scholar
  19. 18.
    A.C. Hindmarsh: Preliminary Documentation of GEARBl; Lawrence Livermore Laboratory Report UCID-30149, Livermore, CA (1976)Google Scholar
  20. 19.
    C.W. Gear:Numerical Initial Value Problems in Ordinary Differential Equations (Prentice-Hall, Englewood Cliffs, NJ 1971)Google Scholar
  21. 20.
    J.F. Gibbons, W.S. Johnson, S. Mylroie:Projected Range Statistics (Dowden, Hutchinson and Ross, Stroudsbourgh, PA 1975)Google Scholar
  22. 21.
    K. Lehovec, A. Slobodskoy: Solid-State Electron.3, 45–50 (1961)Google Scholar
  23. 22.
    R.B. Fair: Proc. 3rd Intl. Symp. on Silicon Materials Science and Technology (77-2); Electrochem. Soc. May 1977, 968–985Google Scholar
  24. 23.
    M.Y. Tsai, F.F. Moreland, J.E.E. Baglin: J. Appl. Phys.51, 3230–3235 (1980)Google Scholar

Copyright information

© Springer-Verlag 1983

Authors and Affiliations

  • C. D. Maldonado
    • 1
  1. 1.Rockwell International CorporationAnaheimUSA

Personalised recommendations