If Au layer is smooth and uniform then you can get signatures of morphology of underlaying thin film.

You can also try X-ray reflectivity to determine the roughness.

Dear MANAS RANJAN SAMANTARAY , certainly if your thin film´s morphology is smaller than the gold thin film deposited for making it conductive, the gold layer could hidden or soften the contours of your thin film morphology. Apart from the method pointed by Muhammad Shahbaz Anwar you could try some other alternative approaches such as, coating with a thinner gold layer (changing the deposition parameters, like deposition speed or the pressure of argon gas in the sputtering system, even changing to some other gas if possible). I faced this same problem with sub-nm and few nm structures and a good solution was to substitute gold by iridium, which form a very thin and uniform layer, with very small crystal sizes, that let us to coat the samples without missing the tiny details.

Another good alternative when you want to observe a dielectric sample on a SEM is to use some charge dissipation system. In this way you can avoid the metal coating and still get good SEM images. In my case, nanostructures fabricated on polymers, we used a N2 cannula that provided a very localized flow on top of the region of interest over the sample, this N2 flow removed the charge without changing the chamber vacuum. The cannula is a thin and flexible plastic tube and was installed in a FE-SEM Zeiss Ultra-Plus. This cannula is motorized and can be placed on top of the sample and removed from the control console. Some other use water vapour to remove the charge.

Alternatively you could analyze your sample morphology without any coating by means of an AFM instead of a SEM. Profilometers (mechanical or optical ) could do the job too.

Hope this helps. Good luck with your research and best regards.

Thank you sir for your precious reply, I will go through the suggestions.

It depends on the thickness you are talking about. Typically gold needs to be >5nm thick before it will start to from a uniform flat layer, thinner than this and you will get island formation. For samples where this is a problem you would typically use a carbon coating.