A thermal model for self-heating in advanced MOS devices.
There are two primary paths for the flow of heat in FinFETs and planar MOSFETS:
- Down towards the substrate of the device
- Along the channel of through the source and drain contacts into the metal layer stack
The thermal model is based on the finite differences method (FDM), the electrical-thermal equivalence can be used to build a thermal resistance network. The power dissipation (or heat) in each element is modeled as a current source. If there are n finite regions, then the temperature at each FDM node can be obtained by solving a system of n linear equations: GT=P
Self-heating is critical in modern devices with three dimensional architectures and highly resistive thermal paths. TherMOS is a tool which estimates the temperature rise within advanced MOS devices due to self-heating. It is developed from ground up using basic python libraries.
Key features are:
- Simulation for different technologies at the change of a button (FinFET, MOSFET)
- Improved run-times by using non-uniform meshing in FDM simulation
- Fast multifin and multigate array simulation
- One-stop-shop for device parameters compiled from literature sources for 7FF and 14nm FDSOI technologies
- Precise estimate of temperature through detailed modeling
- python3.6
- pip 18.1
- python3-venv
- GNU Octave (optional) Additionally, please refere to requirements.txt file in this respository.
We use a python virtual environment to install all the required python libraries using pip.
~$ git cone https://github.com/VidyaChhabria/TherMOS.git
~$ cd Thermal-model
~$ source install.shTherMOS uses pytest for unit tests.
~$ pytest
TherMOS requires a model_parameter file, example model_parameter_FinFET.json, file which specifies the various parameters of the device in consideration. The default parameters in the file model_parameter_FinFET.json and model_parameter_MOSFET.json for a planar 7nm FinFET and 14nm FDSOI planar MOSFET technology and are obtained from literature sources as documented in FinFET_parameters.md and MOSFET_parameters.md respectively.
TherMOS can be used as follows:
python3 src/TherMOS.py <process_type> -device_type <str> -n_gate <int> -power <float> [-n_fin <int> | -width <float>] -active "<int_list>" -percent "<float_list>"
| Argument | Comments |
|---|---|
| -h, --help | Prints out the usage |
| <process_type> | Process and technology specification (str, required) |
| -device_type | NMOS or PMOS device type (required, str) |
| -n_gate | Specifies the number of transistors in the simulation (int, required) |
| -power | Specifies the total power dissipated by the array of transistors(s) |
| -n_fin | Number of fins in FinFET (required, int, use only when <process_type> is FinFET) |
| -width | Width of the MOSFET (required, float, use only when process is MOSFET) |
| -active "int_list" | States the list of gate ids that are dissipating power (list of int, optional) |
| -percent "float_list" | Percentage of power distributed between the active gates (optional, list_of_float) |
After TherMOS completes execution, it generates a temperature report in the output directory which contains the the maximum, and the average temperature rise in the transistor(s).
To view a graphic of temperature distribution within the transistor(s):
cd scripts
octave -r -nodisplay 'visualize_T';
The following outputs are generated by TherMOS:
- temperature.rpt: a report which states the maximum, minimum and average temperature of all the devices simulated.
- T.out: a python object which is an array of temperatures that can be used in Octave to plot the temperature profile.
- T.png: an image with the 3D temperature contour plot of the simulated devices.
- The software only handles transistor arrays that share a common diffusion only.
- Stead-state temperature analysis only.
- Dockerize and CI.
This repository is based on the work done in Impact of Self-heating on Performance and Reliability in FinFET and GAAFET designs
This software is released under the BSD 3-Clause License.
Copyright (c) 2019, The Regents of the University of Minnesota All rights reserved.
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