Confusion about the diode simulation

1

Hello Juan and everybody,

I am working on modeling a 1-D InAs diode. I try to do this by modifying the example diode simulation but I have some questions about the commands there:

  • Could I just state InAs as a material in add_1d_region() command?
  • There are some commands which I don’t understand and can’t find in the manual. I don’t know how to adapt these into the InAs diode:
    CreateSiliconPotentialOnly
    CreateSiliconPotentialOnlyContact
    CreateSiliconDriftDiffusion
    CreateSiliconDriftDiffusionAtContact

My question is basically how I should create my code if I just want to simulate a 1-D diode of a different material.

Bonus:
What should I do to create the doping profile of a simple abrupt P-N junction? I know that I should use the step function but are there any examples which I can look at?

Thank you very much in advance
Yigithan

2

As discussed here:

You just need to set the material parameters, using a function like SetSiliconParameters.

The scripts in python_packages are not documented in the manual. You would have to look at the code. I will work on adding docstrings in the future.
https://github.com/devsim/devsim/issues/146

This function solves the Potential equation in a semiconductor region, assuming equilbrium.

This function sets the boundary condition at a contact for the potential equation in equilibrium.

Setups up the Potential, Electron, and Hole equations for drift-diffusion simulation.

Sets up an ideal ohmic contact for drift diffusion simulation.

Set the material parameters for your material. The existing equations should work for a single region device.

Please check the discussion here:
https://forum.devsim.org/t/simulation-of-simple-2d-sic-diode/328/2

One approach is to use the Step function. However, if you want to have an abrupt junction that is independent of meshing effects, you can have a P region and N region with an interface between them. Then the
CreateSiliconSiliconInterface function would be useful.

3

Thank you very much for the thorough response. So, then I could use those commands (CreateSiliconDriftDiffusion, etc.) just by defining the material properties, right? I mean, they are not just for silicon. I just need to do things like:

ds.node_model(device=device, region=region, name=“IntrinsicConcentration”, equation=“1e13”)
ds.node_model(device=device, region=region, name=“ElectronMobility”, equation=“3000”)

4

Hi @yigithanmkose

Please see this example for using devsim.set_parameter:

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5

Thank you very much! I’ll give it a try

6

Thank you again for demonstrating this. I adapted this into my code; however, I still need help about some additional points:

1- When I run the code from the example, I get this error:

import * only allowed at module level

2- In the example code, it only prints the current but I need to have it as data, so I decided to use the devsim.get_contact_current() command, so should I write “Potential” in the place of “equation”?

3- I need to add surface recombination, and I’ve read your thread with @simbilod but I couldn’t conclude how to use it just like SRH recombination.

I’m sorry if I am being silly but I need to use this software in my paper and thesis, which have a strict timeline so your help is very appreciated.

7
  1. Can you please show the full error and the import line that is failing? Python has multiple ways to do import statements.

For example, if you are not in a module, and you want to import from example.py in the same directory as your script.

from example import *
  1. For saving data, please consider something like:

which calls

as an example.

I do not know the answer to 3.

8

The full error is:

import * only allowed at module level

It happens at this import statement:

from devsim import *

used in a python script at a random directory.

Thank you very much for the help

9

I am not sure what the issue is. This is an issue with the python import system and:

from devsim import *

is a valid line for import. Does:

import devsim

move past this error? Are you using a Python 3 virtual environment?

10

Is your import statement inside of a function?

11

Yes! Since I need to integrate it into an optimization routine, I put this import statement inside a function.

When I try to import these outside of a function, I got:

ModuleNotFoundError: No module named ‘simple_physics’

Additionally, I get no problem with this:

import devsim

12

The full path is devsim.python_packages.simple_physics, unless you have your own version in your working diredtory. Perhaps try:

from devsim.python_packages import simple_physics
13

I settled it like that but instead of using “*”, which means import everything, I imported each function one by one

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