Hi

Please see this paper

https://136.167.2.220/content/dam/files/schools/cas_sites/physics/pdf/Ren/p53.pdf

In conclusion, glassy substrate can be used in SEM image observation. however It should be carful to controll observation set up for getting clear images. I recommand to get a images in lower current than ordinary times.

SEM quality image depend on the electrical conductivity of the deposited layer. So in your case you can use glass as substrate for SEM characterization of your layers with a precaution of a best control of the current intensity as Dr Jung proposed. In the case of the dielectric layers you must deposit 10 nm of a high conductive metal like gold (Au) on the surface for a better collection of the signal.

As the two other comments already indicated, "some" electrical conduction is mandatory. Otherwise your glass get locally charged, and the impinging electrons are reflected from the highly charged areas. I have made the experience, that a higher acceleration voltage has a positive effect on the quality of the resulting SEM micrographs. Some thin metal film on top may also be positive! Good luck, Dirk

I agree with above answers in case of glass substrate, the stub which is using to put your sample you must make a conducting path between sample and stub using carbon tape or paint. So that will give the better image.

Yes you can use glass substrate for SEM micrographs but, for clear micrographs, you have to do something to enhance its conductivity. The possible route might be the Au sputtering. With this sputtering done, you can use comparatively lower voltage i.e. less than 5. In this case you may get the better images.

Good luck!

You can use glass substrate with sample prepared on top of it for SEM analysis. The glass substrate should ideally have a smaller dimension than your SEM sample stub and should also be sputter coated with Au before analysis. While re sizing the glass substrate care should be taken to prevent any damage or contamination to the sample.

For as long as you use conductive coating (either metal or carbon) there is no difference what substrate you use. Glass is as good as any other, or even better due to its smoothness. However, since I often use BSE, I prefer plastic substrate.

If your sample are conductive, you can directly use carbon tape to stick on the edge of you sample. Otherwise, you should deposit Au/Pt on the surface.

DON'T BELIEVE IN CHARGING-DOGMA! Conduction is not always required!

It is a question of the resolution you want to achieve and the equipment you have. I've been working for years with ceramic samples lacking any intrinsic conductivity and without gold sputtering or any other way of arranging conducting paths. I used Leo Gemini 1530 and Zeiss Supra VP 55. If you use low acceleration voltages in the range 1-5 kV and decreased apertures (10-20 micrometer), you could get absolutely awesome micrographs resolving down to some 10-20 nm features. You can check any paper from the list of my publications - they all were produced in this way. Most of them were deposited on glass substrates. You can also take a look at the example here:

http://www.tuhh.de/typo3temp/pics/85f749ff5d.png

http://www.tuhh.de/typo3temp/pics/5795aaf588.png

Roman, Actually some of your pictures display definite charging. They could be improved by applying coating. While coating is not mandatory, in too many cases it is desirable. In addition your are giving advice on GLASS specimen, and to work with glass without coating is much more difficult than with ceramics.

Vladimir, I did not say there is no charging, I said that it is often not as bad as many people think. Moreover, in some cases, coating does not improve anything. For example, while we were working with very porous nanoparticle layers, gold coatings deposited on their surface caused detachment and destruction of the relatively unstable structure, whereas unsputtered films could be investigated with far less problems. Still to add is that if the details you want to image are on the order of 10 nm, even 5 nm thick gold coating will preclude the observation of the actual morphology and will make the microscopy more or less useless. Finally, if you carefully read, I'm giving advice on ceramic coatings on glass substrates, exactly as the author of this thread is asking. Hope that you and someone, who downvoted my answer, can accept this. :-) Happy microscopy, volks!

It's thankful to see so many useful answers, thanks for all of you !!

I totally agreed with all of your comments, charging effects is always be a problem when you use electron source, Gold or Carbon coated layer is one solution.alternatively, Environmental Scanning Electron Microscopy can be used instead to avoid charging.

I agree to most of the above answers, The conductivity of the substrate does matter, but as suggested by Roman Kubrin by reducing the acc. voltage the problem of charging can be handled to a certain extent. With the modern FIG SEMs you can work with acc voltages of as low as 0.5-0.2 or may be even lower, without having a significant effect on the signal to noise ratio. This was/is not possible with the conventional tungsten filament SEM.

Another thing as rightly commented by Roman is that coating doesn't always help. The reason is simple: the coating should be continuous which is not always possible for example in the case of spherical shapes the gold or carbon will not coat the under side of the sphere, thus making the coating discontinuous. And hence, the charging effect will be there in such a case.

if Au sputter coating is not optimal, then you can also use C (carbon) sputtering, I used it very often and mostly I felt it is better than Au.

Coating is not mandatory, as several others have mentioned, it is a matter of the resolution one likes to have. We recently investigated the surface structure of chocolate ... and it appears to melt above a certain magnification - obviously the deposited power was too high. But up to that size, the images were sharp, and many details could be observed. So again, conductivity is not always required!

Cheers, Dirk

Lack of conductivity not only results in poor resolution (which may be ok depending on what you want to find out), but mainly results in electrostatic charges on the surface, and these are nasty and deliver definitely wrong pictures.

Samples can even move in SEM due to the charges.

We use (if not using Au or C sputtering) to apply conductive carbon adhesive (and if we don't use: no useful photos come out).

Chocolate is not an isolator, chocolate is conductive and can dissipate a lot of static charges into its volume!

I don't like to roll up the previous discussion again, but conductivity or better the discharging of the surface during investigation is beneficial (independent of the primary energy).

But if I understood correctly you have already some "sample" prepared/deposited onto your glass substrate. It might mean (you don't comment on that) that the "deposited" additional material/thin film (or whatever) is already somehow conductive and interconnected. Then, you should just use a very small drop of silverpaste on your stub to glue and contact the top surface (with your interested "sample" on the glass substrate) of your sample by simly shifting the substrate into that drop during drying. I would (if not necessary) try to prevent any additional coating especially if the material is already (semi-)conductive as it changes the surface work function and thus the seconary electron yield (and thereby the contrast).

Hi

Please see this paper

https://136.167.2.220/content/dam/files/schools/cas_sites/physics/pdf/Ren/p53.pdf

I do agree with previous comments, I would like  to emphasises that you need to use low pressure vacuum and reduce the beam current. I also suggest to use silver dag between your sample and sample stub. this will also reduce charging effect. That is what I am using recently looking at some glass samples. Alternatively you can use ESEM. Good luck with your analysis

Most of the SEM sample preparation and operational parameters are discussed above in detail.  However, in the unavoidable situation  of gold sputter coating on a glass substrate where the sample is attached, gentle filing of the glass edges forming an obtuse angle with the sample holder surface will help in forming a continuous coated layer improving the conductivity and image resolution.