Introduction to Mextram

The Mextram model gives an excellent description of vertical bipolar transistors in all kinds of processes, amongst which are modern SiGe processes and robust HV processes. It is very efficient in modelling the lowly doped collector epilayer of a bipolar transistor where effects like velocity saturation, base widening, Kirk effect, and impact ionisation play a role. Effects due to having Germanium in the base are also modelled. Furthermore, it contains a full description of the extrinsic regions of a transistor, including substrate current and capacitance. Mextram has formulations for temperature scaling and is easily scalable over geometry. Mextram, level 504, includes full self-heating, in contrast to having self-heating handled by the circuit-simulator. Self-heating is completely implemented in the source code.

Read more about Mextram.

Model definition of Mextram

The model definition of Mextram is available in the following PDF files:

• NPN Model Level 503
• PNP Model Level 503
• Mextram Model Level 504 as well as Simulator specific information on Mextram.
• A list of references

The history of the model can be found here.

Source Code & Library

The source code of Mextram is available here
The file called "device_t504i.c" contains the majority of the Mextram 504 code. If you use the included solver, please make sure that you compile on a system that supports Fortran 77.

The history of the source code can be found here.

The models are included in a dynamically loaded library called SiMKit.

SiMKit is related to the following circuit simulators used within NXP:

• Pstar, the circuit simulator from NXP
• Spectre, the circuit simulator from Cadence
• ADS, the circuit simulator from Agilent

You can read how to download and install the libraries here.

The source code is protected by Copyright © 1991, 2007, NXP.

Additional documentation

Further information on Mextram is available in the following additional documentation:

• "The Mextram bipolar transistor model, level 504.7", J.C.J. Paasschens, R. van der Toorn and W.J. Kloosterman (336kB). Last update March 2008.
• "Introduction to and usage of the bipolar transistor model Mextram", J.C.J. Paasschens and R. van der Toorn, Unclassified Report NL-UR 2002/823, Philips Nat.Lab., 2002 (310kB).
• "Model derivation of Mextram 504. The physics behind the model", J.C.J. Paasschens, W.J. Kloosterman, and R. van der Toorn, Unclassified Report NL-UR 2002/806, Philips Nat.Lab., 2002 (1.10MB). Last update March 2005.
• "Parameter Extraction for the Bipolar Transistor Model Mextram, Level 504", J.C.J. Paasschens, W.J. Kloosterman, and R.J. Havens, Philips Research, Nat.Lab. Unclassified Report 2001/801, 2001 (588kB). Note: the source code for helping implementing some routines in this report is downloadable.
• "Comparison of Mextram and the Vbic95 bipolar transistor model", W.J. Kloosterman, Philips Research, Nat.Lab. Unclassified Report 034/96, 1996 (591kB).
• "Parameter extraction methodology for the Mextram bipolar transistor model", W.J. Kloosterman and J.A.M. Geelen, Philips Research, Nat.Lab. Unclassified Report 003/96, 1996 (491kB).
• "Modelling of Si and SiGe bipolar transistors with the compact model Mextram, level 504", J.C.J. Paasschens and R. van der Toorn, presented at the Workshop Compact Modeling, February 27, 2003 (1.41MB).
• "Mextram (level 504). The Philips model for bipolar transistors", J.C.J. Paasschens, W.J. Kloosterman, and R. van der Toorn, presented at the FSA modeling workshop, September 10, 2002 (529kB).
• "Mextram 504 Experimental Results", J.C.J. Paasschens and W.J. Kloosterman, presented at the Compact Model Council Meeting of March 27, 2000 ( 1.15 MB).
• "Mextram 504", J.C.J. Paasschens and W.J. Kloosterman, presented at the Compact Model Council Meeting of December 9, 1999 590kB)
• "Bipolar Model Standardization Mextram 503.2", W.J. Kloosterman, J.C.J. Paasschens, and D.B.M. Klaassen, presented at the Compact Model Council Meeting of September 29, 1999 (585kB).
• "The Bipolar Transistor Model Mextram", W.J. Kloosterman, J.C.J. Paasschens, and H.C. de Graaff, presented at the Compact Model Council Meeting of December 10, 1998 (430kB).

Related Publications

Further information on Mextram is available on the Mextram documentation page, as well as in the following related publications below:

• "Compact modeling of the noise of a bipolar transistor under DC and AC current crowding conditions", J.C.J. Paasschens, IEEE Trans. Elec. Dev., vol.51, pp.1483-1495, 2004 (133kB).
• "Modelling the correlation in the high-frequency noise of (heterojunction) bipolar transistors using charge-partitioning , J.C.J. Paasschens, R.J. Havens, and L.F. Tiemeijer, in Proc. of the Bipolar Circuits and Technology Meeting, pp.221-224, 2003 (484kB).
• "Modelling the excess noise due to avalanche multiplication in (heterojunction) bipolar transistors" , J.C.J. Paasschens and R.de Kort, in Proc. of the Bipolar Circuits and Technology Meeting, pp.108-111, 2004 (566kB).
• "Dependence of thermal resistance on ambient and actual temperature" , J.C.J. Paasschens, S. Harmsma, and R.van der Toorn, in Proc. of the Bipolar Circuits and Technology Meeting, pp.96-99, 2004 (563kB).
• "Modelling two SiGe HBT specific features for circuit simulation", J.C.J. Paasschens, W.J. Kloosterman, and R.J. Havens, in Proceedings of the Bipolar Circuits and Technology Meeting, pp. 38-41, 2001. Paper 2.2 (337kB).
• "Explorations for high performance SiGe-heterojunction bipolar transistor integration", P. Deixler, H.G.A. Huizing, J.J.T.M. Donkers, J.H. Klootwijk, D.Hartskeerl, W.B. de Boer, R.J. Havens, R.van der Toorn, J.C.J. Paasschens, W.J. Kloosterman, J.G.M. van Berkum, D. Terpstra, and J.W. Slotboom, in Proceedings of the Bipolar Circuits and Technology Meeting, pp. 30-33, 2001 (238kB).
• "Improved compact modeling of ouput conductance and cutoff frequency of bipolar transistors", J.C.J. Paasschens, W.J. Kloosterman, R.J. Havens, and H.C. de Graaff, IEEE J. of Solid-State Circuits, vol. 36, pp. 1390-1398, 2001.
• "Improved modeling of ouput conductance and cut-off frequency of bipolar transistors", J.C.J. Paasschens, W.J. Kloosterman, R.J. Havens, and H.C. deGraaff, in Proceedings of the Bipolar Circuits and Technology Meeting, pp. 62-65, 2000. Paper 3.3 (316kB).
• "A comprehensive bipolar avalanche multiplication compact model for circuit simulation", W.J. Kloosterman, J.C.J. Paasschens, and R.J. Havens, in Proceedings of the Bipolar Circuits and Technology Meeting, pp. 172-175, 2000. Paper 10.1 (310kB).
• "An S-parameter technique for substrate resistance characterization of RF bipolar transistors", S.D. Harker, R.J. Havens, J.C.J. Paasschens, D. Szmyd, L.F. Tiemeijer, and E.F. Weagel, in Proceedings of the Bipolar Circuits and Technology Meeting, pp. 176-179, 2000. Paper 10.2 (266kB).
• "Improved Extraction of Base and Emitter Resistance from Small Signal High Frequency Admittance Measurements", W.J. Kloosterman, J.C.J. Paasschens and D.B.M. Klaassen, Proceedings of the 1999 Bipolar Circuits and Technology Meeting (BCTM'99), pp. 93-96 (299kB).
• "Extension of the Collector Charge Description for Compact Bipolar Epilayer Models", Leo C.N. de Vreede, Henk C. de Graaff, Joseph L. Tauritz, and Roel G.F. Baets, IEEE Trans. on Electron Devices, vol. ED-45, no. 1, pp. 277-285, 1998 (251kB).
• "Advanced modeling of distortion effects in bipolar transistors using the Mextram model", L.C.N. de Vreede, H.C. de Graaff, K. Mouthaan, M. de Kok, J.L. Tauritz, and R.G.F. Baets, IEEE J. of Solid-State Circuits, vol 31, pp. 114-121, Jan. 1996 (824kB).
• "Efficient Parameter Extraction for the Mextram model", W.J. Kloosterman, J.A.M. Geelen and D.B.M. Klaassen, Proceedings of the 1995 Bipolar Circuits and Technology Meeting (BCTM'95), pp. 70-73 (286kB).
• "Modeling of the Collector Epilayer of a Bipolar Transistor in the Mextram Model", H.C. de Graaff and W.J. Kloosterman, IEEE Trans. on Electron Devices, vol. ED-42, no. 2, pp. 274-282, 1995 (542kB).
• "Advanced modeling of distorsion effects in bipolar transistors using the Mextram model", L.C.N. de Vreede, H.C. de Graaff, K Mouthaan, M. de Kok, J.L. Tauritz and R.G.F. Baets, Proceedings of the 1994 Bipolar Circuits and Technology Meeting (BCTM'94), pp. 48-51 (376kB).
• "Distributed high frequency effects in Bipolar Transistors", M.P.J.G. Versleijen, Proceedings of the 1991 Bipolar Circuits and Technology Meeting (BCTM'91), pp. 85-88 (325kB).
• "The Influence of Non-Ideal Base Current on 1/F Noise Behaviour of Bipolar Transistors", M.C.A.M. Koolen and J.C.J. Aarts, Proceedings of the 1990 Bipolar Circuits and Technology Meeting (BCTM'90), pp. 232-235 (259kB).
• "Compact Transistor Modelling for Circuit Design", H.C. de Graaff and F.M. Klaassen, Springer-Verlag, Wien, New York, 1990.
• "Avalanche multiplication in a compact bipolar transistor model for circuit simulation", W.J. Kloosterman and H.C. de Graaff, IEEE Trans. Elec. Dev., vol. ED-36, pp. 1376-1380, 1989 (381kB).
• "Experience with the New Compact Mextram Model for Bipolar Transistors", H.C. de Graaff, W.J. Kloosterman, J.A.M. Geelen and M.C.A.M. Koolen, Proceedings of the 1989 Bipolar Circuits and Technology Meeting (BCTM'89), pp. 245-249 (542kB).
• "Compact Bipolar Transistor Model for CACD, with Accurate Description of Collector Behaviour", H.C. de Graaff, W.J. Kloosterman, and T.N. Jansen, in Proc. Conf. on Solid-State Dev. and Mat. (Tokyo), pp. 287-290, 1986.
• "New Formulation of the Current and Charge Relations in Bipolar Transistor Modeling for CACD Purposes", H.C. de Graaff and W.J. Kloosterman, IEEE Trans. on Electron devices, vol. ED-32, no. 11, pp. 2415-2419, 1985.

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