Hello,

I had already often made images of ITO on glass. It works well if you have a SEM with Schottky or field emitter (due to better brightness of the beam) and essential is to use an Inlense detector, which allows you to go to very small working distances (1mm or even less) and give you high intensity of secondary electrons. The Voltage I used was typical 1 kV. - Don't forget to make conductive connection of the layer to the sample holder.

Best regards

Kirsten

talking the sem image of the thin film was coating on the glod layer

Your glass substrate is the problem. It is an insulator and therefore charging during the SEM measurement. You shoud evaporate a very thin carbon layer on the surfaces you wish to study by SEM before the SEM investigation.

The working distance even for high-resolution mode in SEM is 5 mm.

You will get very nice images if you fulfill the thw point above.

Good luck!

Daniela

Hello,

I had already often made images of ITO on glass. It works well if you have a SEM with Schottky or field emitter (due to better brightness of the beam) and essential is to use an Inlense detector, which allows you to go to very small working distances (1mm or even less) and give you high intensity of secondary electrons. The Voltage I used was typical 1 kV. - Don't forget to make conductive connection of the layer to the sample holder.

Best regards

Kirsten

I agree with the 'inlense' or 'through the lens' detector, that is what we use for smaller working distances. The carbon coating is not necessary because gold and ITO is conductive, but you should have an electrical connection between your stage and the film at the spot where you are imaging.

It looks like your SEM is not well suited for the task.

However you can make a few improvements.

1. It looks like you have not corrected astigmatism (tough to tell for sure, but "it looks like"); correction will improve sharpness of your images.

2. A lot of noise on picture. Slower acquisition (longer scan times) will help.

And, by the way, have you tried higher voltages, like 15 kV? Usually glass charging is not a problem with gold coating, so it may help.

Dear all,

Thanks for your responses. I don't think conductivity is the issue because ITO or gold are conductive and we are using 2 sided copper tape to connect the coating to stage. I'm guessing that tungsten filament with off-lens detector is not the right equipment for this type of imaging.

Kristen I think you are right Schottky or field emission SEM with in-lens detector works best for this (as Pieter also mentioned).

Vladimir: yes i have also tried higher voltage and the results are not any better specially I think because we will pass the very thin film with higher accelerating voltages.

Dear Kristen,

Do you happen to remember how thick were your coatings? because with my samples it seems like we are passing through the coating and the SE signal is from the substrate mostly.

Yes, that reminds me, be carefull with the accelerating voltage. Increasing it indeed increases the accuracy of the electron beam, and thereby the resolution, but it also shoots the electrons deeper into your material, and therefore the secondary electrons (which the beam creates and are normally the ones you detect in a SEM) will emerge from a larger spot on your material, making it less sensitive to surface structure at higher accelerating voltages.