By Saumitra Raj Mehrotra1, Abhijeet Paul1, Gerhard Klimeck1, Dragica Vasileska2, Gloria Wahyu Budiman1

1. Purdue University 2. Arizona State University

This tool simulates a Bipolar Junction Transistor (BJT) using a 2D mesh. Powered by PADRE.

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Version 2.5 - published on 23 Jul 2014

doi:10.4231/D3BR8MH1H cite this

First-Time User Guide View All Supporting Documents



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A bipolar junction transistor (BJT) is a three-terminal device constructed of doped semiconductor material and may be used in amplifying or switching applications. Bipolar transistors are so named because their operation involves both electrons and holes. Although a small part of the transistor current is due to the flow of majority carriers, most of the transistor current is due to the flow of minority carriers, and so BJTs are classified as "minority-carrier" devices. This tool allows Bipolar Junction Transistor (BJT) simulation using a 2D mesh. It allows the user to simulate an npn- or pnp- type of device in common-emitter and common-base configurations. Users can specify the Emitter, Base and Collector region depths and doping densities. Also, the material and minority carrier lifetimes can be specified by the user.
    Typical simulation run time LINEAR: ~ 2 minutes
    Typical simulation run time DISCRETE: ~ 4 minutes
    If you want to know more about the physics of the operation of BJT plese refer to the following slides:
  • BJT Operation Description
    • Example Problems for BJT:
  • BJT Theoretical Exercise
  • h-parameters calculation
    • BJT tool wish list :
    • Upgrading to include HBT simulations.
      Improvements / modifications in subsequent version releases:
    • 2.4 - Updated mobility term for doping dependence. Added Beta Vs Ic plot.
    • 2.3.3 - Fixed Vc voltage sign for npn
    • 2.3.2 - Changed default input deck for run to be faster.
    • 2.3.1 - Fixed overwriting for previous simulation runs
    • 2.3 - Improved mesh density for Linear case around 2*Le+Wb+2*Lc (Le/c=diffusion lengths;Wb=base width). Mesh density gradient calculated depending on doping in the region for better resolution.
    • 2.2 - Working for Common Base mode of operation. Added fermi level plot in equilibrium energy band diagram. Added option for minority carrier lifetime (us) and Diffusion constant (cm2/s) for Emitter,Base and Collector regions.
    • 2.1 - 1D Linear BJT simulation capability added.3D plots added for better visualization for 2D discrete BJT simulations.
    • 2.0.1 - Added simulation progress bar.
    • 2.0 - It is now a full 2D simulator allowing users to plot 1D plots along the depth like conduction/valence band, electron/hole density, electric field, potential, recombination rate, current density.
    • 1.22 - Fixed for memory issue by trimming output files.
    • 1.12 - Update for improved quality of output curves. No overlapping of curves now.
    • 1.11 - Discrete BJT simulator launched with output characteristics and Gummel plot.
    • 1.1 - 1D linear BJT simulator updated for minor bugs.
    • 1.0 - 1D linear BJT simulator launched.

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    Cite this work

    Researchers should cite this work as follows:

    • Saumitra Raj Mehrotra; Abhijeet Paul; Gerhard Klimeck; Dragica Vasileska; Gloria Wahyu Budiman (2014), "BJT Lab," (DOI: 10.4231/D3BR8MH1H).

      BibTex | EndNote


    1. nanoelectronics
    2. BJT
    3. Padre
    4. NCN Supported
    5. NCN@Purdue Supported
    6. nanoelectronics
    7. BJT
    8. NCN Supported
    9. NCN@Purdue Supported
    10. Padre
    11. device simulations
    12. diffusion
    13. diffusive transport
    14. drift-diffusion
    15. fermi level
    16. Gummel plot
    17. Maxwell Boltzmann
    18. semiconductors
    19. Sharfetter-Gummel
    20. TCAD
    21. transport/Drift-Diffusion
    22. device simulations
    23. diffusion
    24. diffusive transport
    25. drift-diffusion
    26. fermi level
    27. Gummel plot
    28. Maxwell Boltzmann
    29. semiconductors
    30. Sharfetter-Gummel
    31. TCAD
    32. transport/Drift-Diffusion
    33. device simulations
    34. diffusion
    35. diffusive transport
    36. drift-diffusion
    37. fermi level
    38. Gummel plot
    39. Maxwell Boltzmann
    40. NCN Supported
    41. NCN@Purdue Supported
    42. semiconductors
    43. Sharfetter-Gummel
    44. TCAD
    45. transport/Drift-Diffusion
    46. nanoelectronics
    47. BJT
    48. device simulations
    49. diffusion
    50. diffusive transport
    51. drift-diffusion
    52. fermi level
    53. Gummel plot
    54. Maxwell Boltzmann
    55. NCN Supported
    56. NCN@Purdue Supported
    57. Padre
    58. semiconductors
    59. Sharfetter-Gummel
    60. TCAD
    61. transport/Drift-Diffusion