image.png

BTW, the “photodiode” is one of the standard PN-junctions. You can implement them any way you want. The advantage of using the pre-made cell is that (1) this is a layout that is probably silicon-proven, and (2) I guess there is a simulation model for that. I am not totally sure, but this looks like an n-well-to-substrate diode, which makes sense, as this is the deepest PN junction, and good for visible light (if this is what you want to use).

@User the relevant component version here is probably

open_pdks

. You could look into the GitHub changes, or @User knows this.

If you cloned from GitHub, just do

git pull

inside the relevant directories.

@User sorry for all the follow-up, but when I run git pull on my skywater_pdk directory, I have the following error

connie@connie-GE75-Raider-10SE:~/skywater-pdk$ git remote -v
origin	<https://github.com/google/skywater-pdk> (fetch)
origin	<https://github.com/google/skywater-pdk> (push)
connie@connie-GE75-Raider-10SE:~/skywater-pdk$ git pull
Fetching submodule libraries/sky130_fd_io/latest
Could not access submodule 'third_party/make-env'
Fetching submodule libraries/sky130_fd_sc_hvl/latest

where it says it can't access a submodule, even though I have the branch checked out?

@User: I have recently stopped pulling and installing skywater-pdk myself, but now I just let open_pdks automatically pull all the repositories, which it puts in the

sources

directory, and

make update

will update all repositories if needed. I ran that just now and didn't encounter any errors, so I'm not sure why you're getting an error on

git pull

. Like Harald, I can only suggest deleting skywater-pdk and reinstalling (or, as I said at the beginning, just let open_pdks do it for you). BTW, there was no need for you to update the skywater-pdk repository (which hasn't ever changed except for the guys at Google constantly messing around with the documentation), or uninstall anything. All you needed to do was to cd to open_pdks, do

git pull

and

make

and

sudo make install

.

@User@User Thanks for all your help! I was able to update my open-pdk and pdk library and use the photodiode in magic

has the same cross sectional view. Kind regards

pd.pdf

I am not an expert in photodiode physics, so it would be helpful to have somebody knowledgeable weigh in on the interpretation of SkyWater's photodiode rules.

@Tim Edwards here goes the article where I have found the cross section. In fact I was looking for the mask associated with the photo layer however, as You have mentioned, seems that it does not exist. It seems also that the photo active PN junction is between deep N-well and the P-well. Do You know anybody here, who could those rules and give some hints about the device ?