⚙️ Paramus Physical Edition

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Generate BSIM4 model cards from five fundamental physical parameters

Paramus Physical Edition is a Python-based utility that automatically generates
BSIM4 SPICE model cards (.sp) from a small set of key MOSFET physical parameters:

tox / Na / Vfb / μ0 / L/W

It is designed for device engineers, students, and researchers who want a clean and interpretable
bridge between MOSFET physical characteristics and compact modeling (BSIM4).

📁 Project Structure

Paramus/
│
├── modelcard/
│   ├── build.py               # Inserts parameters into the BSIM4 template
│   ├── template_bsim4.tpl     # BSIM4 model card template
│
├── physical/
│   ├── extract.py             # Loads presets & interprets physical parameters
│   ├── poisson.py             # Surface potential & Vth calculation
│   ├── iv.py                  # Simplified I–V model (Ids, gm)
│   ├── mapping.py             # Physical values → BSIM4 parameter mapping
│
├── presets/
│   ├── nmos_90nm.json
│   ├── nmos_130nm.json
│   ├── pmos_90nm.json
│   ├── pmos_130nm.json
│
├── paramus.py                 # Main entry point
└── README.md

🚀 How to Use

1. Move to the Paramus directory

cd Path/To/Paramus

2. Generate a model card

NMOS 130nm

python paramus.py --node 130nm --type nmos --out model.sp

PMOS 130nm

python paramus.py --node 130nm --type pmos --out pmos130.sp

NMOS 90nm

python paramus.py --node 90nm --type nmos --out nmos90.sp

Generated output example:

model.sp

🔧 Input Parameters (5 Physical Quantities)

Parameter	Description
tox	Gate oxide thickness
Na	Channel doping concentration
Vfb	Flat-band voltage
μ0	Low-field mobility
L/W	Device geometry (length & width ratio)

🧠 Model Generation Flow

[ Physical Model ]  physical/
    extract.py   → Load & process physical parameters
    poisson.py   → Compute φs, Vth0, Cox, Es
    iv.py        → Compute Ids, gm
    mapping.py   → Map physical values to BSIM4 parameters

[ Template ]     modelcard/
    template_bsim4.tpl
    build.py     → Embed mapped values into template

[ Execution ]
    paramus.py   → Outputs model.sp

📘 Source Code Overview

● `physical/extract.py`

Loads JSON preset
Performs unit normalization
Prepares data for Poisson / IV stages

● `physical/poisson.py`

Computes:

Surface potential φs
Threshold voltage Vth0
Oxide capacitance Cox
Surface electric field Es

● `physical/iv.py`

Implements simplified MOSFET I–V behavior:

Ids(Vgs, Vds)
gm, gds
Linear / Saturation regions

● `physical/mapping.py`

Maps physical quantities to BSIM4 parameters:

μ0 → u0, ua, ub
tox → tox, epsrox
φs → vth0
SCE terms → dvt0, dvt1, eta0

● `modelcard/build.py`

Replaces `` placeholders
Outputs the final BSIM4 model card

🎯 Custom Presets

To use your own MOSFET parameters:

python paramus.py --preset presets/my_nmos.json --out my_model.sp

📄 BSIM4 Template (template_bsim4.tpl)

A standard BSIM4 template.
`` entries are filled automatically by build.py.

📄 Hybrid License

Paramus Physical Edition adopts a hybrid licensing model designed to handle code, documentation, and figures appropriately.

Item	License	Description
Source Code	MIT License	Free to use, modify, redistribute
Documentation / Text Materials	CC BY 4.0	Attribution required
Figures / Diagrams / Generated Plots	CC BY-NC 4.0	Non-commercial use only
External References	Original license applies	Cite sources properly

📬 Contact

For requests, improvements, or extensions to the physical modeling,
please open an Issue in the repository.

👤 Author

📌 Item	Details
Name	Shinichi Samizo
GitHub