## Introduction

*PADRE* simulates the electrical behavior of devices under steady
state, transient conditions or AC small-signal analysis. Multiple
devices can be treated, along with lumped element circuit networks.
*PADRE* can simulate physical structures of arbitrary geometry--including
heterostructures-with arbitrary doping profiles, which can be obtained
using analytical functions or directly from multidimensional process
simulators such as *PROPHET* or *BICEPS*.

For each electrical bias, *PADRE* solves a coupled set of partial
differential equations (PDEs). A variety of PDE systems are supported
which form a hierarchy of accuracy:

- electrostatic (Poisson equation)
- drift-diffusion (including carrier continuity equations)
- energy balance (including carrier temperature)
- electrothermal (including lattice heating)

A variety of physical mechanisms are supported within these
formulations, including comprehensive representations of
carrier mobility, generation/recombination, and boundary conditions.
*PADRE* results can be supplemented by the Monte Carlo device
simulator *SMC*
which is more appropriate for studying hot carrier effects such as
MOS substrate and gate current.
Solutions are represented on a finite element grid within the space
of the device. *PADRE* supports box discretizations and general
finite element discretizations through non-uniform triangular grids,
which can be refined during the simulation process.

Compared with other device simulation programs, *PADRE* has a number
of important features:

- Energy balance equations
- Heterostructures
- Enhanced models
- More automatic error-controlled grid generation
- IV predictor-corrector continuation methods
- Modular vector/parallel assembly
- Vector/parallel linear algebra
- Mixed coupled/decoupled nonlinear iterations

## Contacts

- Mark R. Pinto (research!pinto), MH 6E-306
- Michael J. McLennan (mhcnet!mmc), ALC 2C-226