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 new 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 unphysical parameter (for example, current crowding is modeled, using only one parameter)
   
• Symmetry of the equivalent circuit, thanks to a splitted 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
  

Simucad 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 is part of the SmartLib™ product-independent model library. It can be accessed within SmartSpice™ as level 500
  

Rev. 101807_03