Short answers: NO and NO.

Longer answers: The value Ra is an average over all topography. It is not a measurement over a step of a film. So, Ra is not a height of a film, and it is wrong to report it as a thickness of a film. The better choice is to measure thickness by measuring across a boundary line that separates uncoated and coated regions.

Short answers: NO and NO.

Longer answers: The value Ra is an average over all topography. It is not a measurement over a step of a film. So, Ra is not a height of a film, and it is wrong to report it as a thickness of a film. The better choice is to measure thickness by measuring across a boundary line that separates uncoated and coated regions.

Thank you sir for your kind acknowledgement. This surely clears my doubt for analysing my results in a better manner. 

I did go through some literature and found " AFM Scratch test" to get thickness of thin films. Does this test needs some serious conditions for tests to do? Kindly please guide me with your expertise. Thank you.

A scratch test is a reasonable method. It has its own problems. The methods should be followed and the measurements done on a repeated set of samples to get statistics. Another good method is to deposit a film with part of the substrate covered by a mask. Image over the step created by the mask.

Aah! I guess I can surely work with your idea sir. Thank you so much for the valuable suggestions given by you. I really appreciate them.

Sir, take look here: https://www.researchgate.net/post/Parameters_for_surface_roughness

I attached pdf with roughness parameters. Ra, Rz, Rmax (and others) are roughness parameters but not linear height values.

No, They are totally different. Ra is the surface rouhness of the film. the technique for the measurement of the thin film can be choosen according to the film is transparent or not. You can check from the papers, 

1. AFM and SEM studies of CdS thin films produced by an ultrasonic spray pyrolysis method

By:Baykul, MC (Baykul, MC); Balcioglu, A (Balcioglu, A)

MICROELECTRONIC ENGINEERING

Volume: 51-2, Pages: 703-713

DOI: 10.1016/S0167-9317(99)00534-1

Published: MAY 2000

2. Structural and optical properties of CdS nanocrystals grown in water-soluble diblock copolymer

By:Baykul, MC (Baykul, M. Celalettin)[ 1 ] ; Ruzgar, H (Ruzgar, Hilal)[ 1 ] ; Arman, E (Arman, Emine); Bas, Y (Bas, Yasemin); Butun, V (Butun, Vural)

Book Author(s):Bechstedt, F (Bechstedt, F); Zahn, DRT (Zahn, DRT)

 PHYSICA STATUS SOLIDI C: CURRENT TOPICS IN SOLID STATE PHYSICS, VOL 7, NO 2

Book Series: Physica Status Solidi C-Current Topics in Solid State Physics

Volume: 7, Issue: 2, Pages: 423-426

DOI: 10.1002/pssc.200982468

Published: 2010

Thank you sir, I will go through the articles provided by you. 

Ra does not measure the thickness of the thin film, but the roughness of the surface.

Dear Saurav,

A scratch test can measure the thickness of the film but it may not be the accurate method because it also affect the substrate where the film deposited. Although these amplitude parameter provide the topography of the topmost surface of the film. If you want to measure the thickness of the film, ToF-SIMS instrument will give you valuable measurement and analysis.

Best of luck.

Sorry to come up late to this discussion.

You mentioned that your films must be

No you can not take the Ra value as the thickness of the sample. Ra is just the information about the roughness of the surface. But may be you can measure the thickness of the sample like that. ıf you start to scan from the undeposited place on the subrate and continue to scan to the sample. Maybe you can measure the thickness of the sample from the height variation which is between the top of the substrate and highest value of the sample.