This page updated 01 March 2015

Bipole3 Frequently Asked Questions



What is Bipole3?

Bipole3 is a very fast semiconductor device numerical simulation software for PC platforms. It is designed for bipolar transistors (including BJT and HBT structures), but also includes diodes, photodiodes and MOSFET simulation.



Who uses Bipole3?

Industry TCAD and circuit CAD groups use this software. Some such groups use Bipole3 as a stand-alone simulation package. Other groups also have access to 'full 2D' simulators and use Bipole3 for initial design optimization and training. Bipole3 is also extremely useful for university research and for upper year undergraduate courses in semiconductor devices.



Why use Bipole3?

Bipole3 is extremely fast (typically 1/100th the execution time of conventional simulators) and has very fast engineer set up time (typically first input file set up within minutes)



Why is Bipole3 so fast ?

The program uses vertical one dimensional numerical simulations (emitter through to collector), coupled to horizontal (direction of base current flow) numerical simulations for majority carrier transport . In addition, the device is divided into space charge and neutral regions (whose boundaries are bias dependent and computed during solution) so that Poisson's equation and the transport equations are partially decoupled.



The sidewall regions are treated separately by Poisson's equation for sidewall capacitance and a full 2D neutral region minority carrier transport solution for sidewall injection. This combination in effect provides a complete device simulation including all major 3D properties for an execution time which is typically 1/100 th that of a 'full 2D simulator'.



Is Bipole3 accurate?

This software has evolved over the past 25 years and the results are being continually compared to experimental data and to full 2D simulations. At present, reliable predictions have been verified in HBTs with ft values above 100 GHz.



Are extracted SPICE parameters reliable?

Using the SPI Extension Module, 2G6 SPICE files are generated during simulation (no additional manual intervention required). The bias range for the parameter extraction is defined by the user. Bipgraph plots are available for key performance parameters IC, IB Gummel plots, current gain, ft versus IC. Each graph contains both the Bipole3 generated plot and the plot generated using the extracted SPICE parameters. Thus visual observation of the extraction precision is immediately made. Furthermore, the lst file contains a numerical summary of the accuracy of the extraction.



Is Bipole3 expensive?

This software is considerably less expensive than conventional 2D simulation packages. University and Personal use Licences are now available at greatly reduced prices. A simplified free software package Bipole3-Basic is available by download from this site. This is a simplified version of Bipole3 and is suitable for some post-graduate research topics.



What is the input and how is it set up?

The input consists of impurity profiles (analytic or tabular) plus mask layouts. Physical Model data may be optionally specified. The impurity profiles may be specified as generalised quasi Gaussian functions or a tabular data (obtained from SIMS or other experimental techniques or from process simulators). The input is setup as a text file using a text editor. This includes dimensions for the mask templates. A large number of example input files are supplied with the software to accelerate the setting up process for a particular device.

Must all the mask dimensions be specified?

No, this is not necessary. Options exist for specifying only emitter dimensions, using built-in design rules to provide very fast set-up times for initial studies of a new device. This reduces the number of mask input parameters from typically 17 to 2 (emitter width and length) and is suitable for many preliminary studies.



Can I examine examples of Bipole3 simulations ?

See the Bipole3 Tutorial Guide on this web site for a wide range of worked examples. The results of devices simulated for the Bipole3-Basic Tutorial Guide may also be downloaded from this web site and viewed with the graphics post-processor Bipgraph.



How is the output presented ?

The output is viewed using Bipgraph, an easy to use graphics post-processor. Output graphs consist of both internal quantities (carrier and electric field distributions, etc.) and terminal characteristics (dc and high frequency). Numerical output data is also contained in a list file.



Does Bipole3 perform high frequency simulation?

For ft and fmax osc results, the small signal high frequency extraction is built-in to the basic program.



Does Bipole3 include A Hydrodynamic Model for high frequency simulation?

In V5.2 release available March 2005, a Hydrodynamic Model is included. For ft values greater than 50 GHz this model is necessary for good accuracy. The Hydrodynamic Model in Bipole3 has been tested using our own and published HBT device details with ft values well in excess of 200 GHz and gives excellent ft vs IC predictions.

The full numerical Non Equilibrium Transport model option, which has been available for several years in Bipole3, gives excellent prediction of BVceo for devices with ft well above 200 GHz.



Can Bipole3 simulate MOSFETs ?

Yes, an Extension Module MOSCALC was introduced for simulation of basic prototype MOSFET structures. This is also based on two coupled one dimensional numerical solutions of the transport and Poisson's equation with bias dependent space charge regions determined during simulation. This module has not received the same extensive industrial evaluation as for bipolar transistors but has nevertheless proved very useful for educational purposes.