Hopefully this is the right group for these two questions:
1) For a photodiode, the series resistance is due to the contact resistance (as one factor), but what is the source of a photodiode shunt resistance? Is it simply due to the inherent resistence of the junction to the current flow due to diffusion in photovoltaic mode and drift currents in photoconductive mode?2) Also, in regards to a layout of a basic PN junction photodiode, if you have an N-Well in a P-epi photodiode, with P+ contacts around the N-Well, and N+ contacts in the N-well, the depletion region extends mostly into the P-epi (as it is lighter doped). However, does it matter whether the N+ contacts cover the entire N-well or are just placed at its edges?