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## Diode example solved but strange

Posted 14.11.2012 12:10 GMT-05:00 Parameters, Variables, & Functions Version 4.3a 3 Replies

Hi

I tried to solve the semiconductor diode example from the model library but simplifying it a bit. In particular, I discarded the rounded corner and just made it a text book like pn-junction. It seems I can solve the problem using electrostatics and diffusion for n- and p-type carriers. However, I dont trust the solution (hole concentration high at high potential).

It would be great if someone could have a brief look at my model and tell me if there is anything that's obviously wrong.

When solving, I get the message that Comsol failed to evaluate the variable Jacobian for the hole concentration. I guess that has something to do with large gradients being present which originate from the large changes in carrier concentrations.

Any help is much appreciated.

I tried to solve the semiconductor diode example from the model library but simplifying it a bit. In particular, I discarded the rounded corner and just made it a text book like pn-junction. It seems I can solve the problem using electrostatics and diffusion for n- and p-type carriers. However, I dont trust the solution (hole concentration high at high potential).

It would be great if someone could have a brief look at my model and tell me if there is anything that's obviously wrong.

When solving, I get the message that Comsol failed to evaluate the variable Jacobian for the hole concentration. I guess that has something to do with large gradients being present which originate from the large changes in carrier concentrations.

Any help is much appreciated.

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3 Replies Last Post 18.11.2012 20:54 GMT-05:00