Modella

Lateral PNP Bipolar Model

Dedicated Lateral PNP Model

The MODEL-LAteral model developed by Philips N.V. provides an accurate model dedicated to lateral PNP devices.

This model is based on a totally new approach, accounting for the complex bi-dimensional structure of lateral transistors. Modella allows the simulation of lateral devices using real physically based parameters, instead of using less accurate empirically-modified models, such as Gummel-Poon. With Modella, lateral PNP bipolars do not lack an accurate model anymore.

Influence of excess-phase on current gain

Ic vs. Vce characteristic

 

Major Improvements

Modella benefits from the following improvements with regard to the older Gummel-Poon model:

  • More complex resistive network, using more internal nodes
  • Separation of bottom and sidewall components, describing the 2D structure of the transistor
  • No nonphysical parameter (for example, current crowding is modeled, using only one parameter)
  • Symmetry of the equivalent circuit, thanks to a split base resistance
  • Equations derived from PNP formulations
  • No iterative process used in equations, resulting in short simulation times

Physically-Based Lateral Bipolar Model

Modella accounts for the bi-dimensional structure of lateral PNP devices, modeling physical effects such as:

  • Explicit modeling of inactive regions
  • Excess-phase shift for current and storage charges
  • Charge storage
  • Temperature
  • High-injection
  • Built-in electric field in base region
  • Bias-dependent Early effect
  • Low-level non-ideal base currents
  • Hard and quasi saturation
  • Weak avalanche
  • Current crowding and conductivity modulation of thebase resistance
  • Hot carrier effects in the collector epilayer
  • Split base-collector depletion capacitance

Silvaco Implementation

  • Modella is compatible with VZERO and BYPASS options in order to achieve great speed performance
  • Internal warnings and diagnostics provide valuable information to help finding convergence issues
  • User-friendly parameters checking; user is kept aware of every clipped parameter
  • Device internal variables (currents, conductances, charges...) can easily be accessed like any other parameter
  • Modella model can be accessed within SmartSpice as level 500

Rev. 012114_04