nanohub-padre

A Python library for creating and running PADRE semiconductor device simulations.

Overview

nanohub-padre provides a Pythonic interface to generate PADRE input decks, making it easier to set up complex device simulations programmatically. PADRE is a 2D/3D device simulator that solves the drift-diffusion equations for semiconductor devices.

Features

• Pythonic Interface: Define meshes, regions, doping profiles, and solver settings using Python objects
• Device Factory Functions: Pre-built functions to create common devices (PN diode, MOSFET, BJT, solar cell, etc.)
• Complete PADRE Support: Covers mesh generation, material properties, physical models, and solve commands
• Validation: Built-in parameter validation and helpful error messages
• Examples: Ready-to-run examples for common device structures

Installation

pip install nanohub-padre

Or install from source:

git clone https://github.com/nanohub/nanohub-padre.git
cd nanohub-padre
pip install -e .

Quick Start

Using Device Factory Functions (Recommended)

from nanohubpadre import create_mosfet, Solve, Log

# Create an NMOS transistor with one line
sim = create_mosfet(
    channel_length=0.05,
    device_type="nmos",
    temperature=300
)

# Add solve commands
sim.add_solve(Solve(initial=True))
sim.add_log(Log(ivfile="idvg"))
sim.add_solve(Solve(v3=0, vstep=0.1, nsteps=15, electrode=3))

# Generate the input deck
print(sim.generate_deck())

Building from Scratch

from nanohubpadre import (
    Simulation, Mesh, Region, Electrode, Doping,
    Contact, Models, System, Solve
)

# Create simulation
sim = Simulation(title="Simple PN Diode")

# Define mesh
sim.mesh = Mesh(nx=100, ny=3)
sim.mesh.add_x_mesh(1, 0)
sim.mesh.add_x_mesh(100, 1.0)
sim.mesh.add_y_mesh(1, 0)
sim.mesh.add_y_mesh(3, 1)

# Define silicon region
sim.add_region(Region(1, ix_low=1, ix_high=100, iy_low=1, iy_high=3, silicon=True))

# Define electrodes
sim.add_electrode(Electrode(1, ix_low=1, ix_high=1, iy_low=1, iy_high=3))
sim.add_electrode(Electrode(2, ix_low=100, ix_high=100, iy_low=1, iy_high=3))

# Define doping
sim.add_doping(Doping(p_type=True, concentration=1e17, uniform=True, x_right=0.5))
sim.add_doping(Doping(n_type=True, concentration=1e17, uniform=True, x_left=0.5))

# Set contacts
sim.add_contact(Contact(all_contacts=True, neutral=True))

# Configure models
sim.models = Models(temperature=300, srh=True, conmob=True, fldmob=True)
sim.system = System(electrons=True, holes=True, newton=True)

# Solve
sim.add_solve(Solve(initial=True))

# Generate and print the input deck
print(sim.generate_deck())

Device Factory Functions

The library includes factory functions for common devices:

Function	Description
create_pn_diode	PN junction diode
create_mos_capacitor	MOS capacitor for C-V analysis
create_mosfet	NMOS/PMOS transistor
create_mesfet	Metal-semiconductor FET
create_bjt	NPN/PNP bipolar transistor
create_schottky_diode	Schottky barrier diode
create_solar_cell	PN junction solar cell

Examples

The examples/ directory contains Python equivalents of common PADRE simulations:

• pndiode.py: PN junction diode I-V characterization
• moscap.py: MOS capacitor C-V analysis
• mosfet_equivalent.py: NMOS transistor transfer and output characteristics
• mesfet.py: Metal-Semiconductor FET simulation
• single_mosgap.py: Simple oxide-silicon structure

Device factory examples in examples/devices/:

• pn_diode_example.py: PN diode using factory function
• mosfet_example.py: NMOS using factory function
• bjt_example.py: NPN BJT using factory function
• solar_cell_example.py: Solar cell using factory function

Run an example:

PYTHONPATH=. python3 examples/pndiode.py > pndiode.inp
padre < pndiode.inp > pndiode.out

Supported Commands

nanohub-padre supports all major PADRE commands:

Category	Commands
Mesh	MESH, X.MESH, Y.MESH, Z.MESH
Structure	REGION, ELECTRODE
Doping	DOPING (uniform, Gaussian, ERFC, file)
Boundaries	CONTACT, INTERFACE, SURFACE
Materials	MATERIAL, ALLOY
Models	MODELS
Solver	SYSTEM, METHOD, LINALG, SOLVE
Output	LOG, PLOT.1D, PLOT.2D, PLOT.3D, CONTOUR, VECTOR
Control	OPTIONS, LOAD, REGRID, ADAPT

Documentation

Full documentation is available at https://nanohub-padre.readthedocs.io/

Testing

Run the test suite:

pytest tests/ -v

License

MIT License - see LICENSE file for details.

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.