Hi,

You can do IV simulation with the IMPACT.I model so that you can check currents above its breakdown point.

And in addition you can simulate some performance (e.g. E-field, etc.) at VB+VE (i.e. above breakdown) by intentionally excluding the IMPACT.I model.

Best, MJ

Dear Wendi,

welcome!

the dark current of the avalanche photodiode diode is due to the revrse saturation curent which will be multiplied in the space charge region. One of the ways to suppress this current is to reduce the simulation temperature such that reverse saturation current gets smaller than the rate of the single photon incidence rate.

You can also decrease the diode area. In conclusion you must reduce the reverse saturation current to be much less than the photo generation rate.

wish you success

Dr. Zekry - Thank you for your reply. Do you mean that by decreasing the reverse saturation current, it is possible that the avalanche won't be triggered even when the bias voltage is beyond breakdown point during a small period of time in the simulation?

Best,

Wendi 

Dear  Myung-Jae-Thanks so much for your comment. However, I guess I can not simply turn off the impact model because to simulate SPAD photon generated avalanche, the incident photon has to create free carriers which will lead to impact ionization in the space charge area, if we exclude the impact model, then the photon induced avalanche would not happen either. 

Best,

Wendi 

Wendi,

Yes. This is what i mean. It is so that the dark current at breakdown is equal to M xIs where M is the multiplication factor and Is is the reverse saturation current and M is the multiplication factor. The multiplication factor M can be controlled by the reverse voltage on the diode while Is can be controlled by area and temperature as i hinted in my previous post.

wish you success