contact boundary conduction

[Zhi-Gang Yu]

Dear Juan,

In the devsim examples, the contact's boundary condition is of Drichlet type, with carrier densities being equal to those in the adjacent doped semiconductor. 

Could you advise how to construct a general contact model with a Robin boundary condition, 

D \gradient p = s (p - p0)

The physics behind it is the surface recombination.    

Best wishes

Zhi-Gang

[Juan Sanchez]

Hi Zhi-Gang,

It appears that such a boundary condition would be similar to the
Schottky contact that was discussed in this thread:
https://groups.google.com/g/devsim/c/uTB4G30eBIc/m/4BtZMRPAAAAJ

Specifically discussed in this example:
https://groups.google.com/g/devsim/c/uTB4G30eBIc/m/Lj7kTM8vEAAJ

I believe the proper implementation would be to set the boundary
condition using the contact equation command:
https://devsim.net/CommandReference.html#devsim.contact_equation

where the "node_model" option would be the:
s(p - p0)

and the "edge_model" would be the:
D \gradient p

Note that the node_model is integrated with respect to the
"NodeVolume" model during the equation assembly. So I would recommend
modifying the "node_model" equation to:
s*(p - p0)*ContactSurfaceArea/NodeVolume

so that the contact surface area is used instead.

The built in node models are listed here:
https://devsim.net/models.html#id5

The "edge_model" is integrated with respect to EdgeCouple, so it would
be unmodified:
https://devsim.net/models.html#models-edge

Please let me know if you have any questions.

Regards,

Juan

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[Zhi-Gang Yu]

Dear Juan,

Thank you for your detailed explanation. I'm trying to write the code according to your suggestion.

Best wishes

Zhi-Gang