You could use sputter coating to coat metallic thin film coatings in nanometer range.

Applied current and time used for sputter coating will give you an idea about how thick is the coated thin film. 

You could observe the cross section of the thin film along with the substrate using a high resolution scanning electron microscope  to measure the thickness of your thin film.

Chemical Vapor Deposition (CVD) would be another method to grow/coat thin films on your substrate.

Cheers

Lijo

Lijo,

Thank you for your answer, but I do not think an SEM could be used to measure a 10 Angstrom thick film (1E-9 meter).  If I want the magnified image to be only 1 mm wide (1E-3 meter), I would need a magnification of 1E-3/1E-9 = 1E6 or 1 Million.

Brad

Yes Brad.. I know that to get such an incredible magnification with SEM is not easy. But nowadays the advanced technologies help us to reach beyond our expectations. Nova NanoSEM 50 series models 450 and 650 can provide a magnification from the range 35 X - 1,000,000 X . We have both these series of SEM machines in our university core lab.  Usually I need a magnification of maximum 100,000 X. So I use other SEM from QUANTA series (200, 600 etc). 

FYI : http://www.rdmag.com/product-releases/2010/12/afm-and-sem-specifications-guide-fei-companys-nova-nanosem-50-series

Cheers

Hello Brad

I good technique to measure and monitor you film thickness in the low Angstrom range could be X-ray fluorescence analyis. You can find numerous companys who sell systems for exactly this topic. Another option could be Xray reflectometry.

In my research activites I often have to analyze thin films in the Ang. range and we do this using grazing incidence XRF and XRR. In principle it works quite nicely also for very low thicknesses.

XRR - X-ray Reflectivity

https://www.researchgate.net/post/What_depths_can_one_typically_probe_with_XRR_X-ray_Reflectivity_Reflectometery?_tpcectx=profile_questions

Dear colleague Brad

Herein fined three methods to measure film thickness, you can chose the suitable one according to  condition of the film.

Film thickness can be checked by

1-    An interferometric method, more details is available at: TOLANSKY S. Multiple beam interferometry of surfaces and films. London: Oxford University Press, 1988: 147.

2-    Using mass of the film, m according to the next details::

 W1 is the weight of cleaned substrate

W2 is the weight of cleaned substrate plus film

ΔW=W2-W1= the weight of the film

ΔW=mg

m = ΔW/g

m=ρXV   ;   ρ, is the density of film material and V is the volume of the film                   

the Volume  = (Width X Length X Thickness) of the film

3-    SEM or AFM  (film-substrate ) cross section

you could use ellipsometry

CAFM, TAFM and TEM measurement techniques. You can check following article.

Thanks everyone for a good range of useful suggestions and references!  I really appreciate your help.

SEM - We are limited to ~20,000 X for high quality images.

XRF - We have equipment and will investigate.

Ellipsometry - We have tried variable angle spectroscopic ellipsometery (VASE).  For an intended 50A film we got the best model fit with a 30A base layer plus a 60A rough surface layer.  The thick rough surface layer indicates that the film may be inhomogeneous or discontinuous.

Good Luck, Brad :-)

What kind of XRF setup do you have? Depending on the geometry, the x-ray source and the material you want to analyze you might be below the lower limit of detection for your setup. so do not be puzzled if you do not see anything on the first attempt.

you can tune the sensitivity to some extent by choosing a very shallow angle between sample and exciting beam (grazing incidence XRF mode). i will leave you with some examples, although they are much more sophisticated than what I think you will need.

Article Characterization of High-k Nanolayers by Grazing Incidence X...

Article Reference-free, depth-dependent characterization of nanolaye...

 you can use spectroscopic ellipsometry and by choosing the convenient model and get the best fit you will find the layer`s thikness.

For a quick and rough (factor of 2) estimate, you could also get a used Veeco 4 point probe (normally used for silicon wafers but will work on thin metal films also) and measure a sheet resistance Rsh for the film (make sure the four co-linear probes are in center of sample to avoid edge effects). Place substrate under probe, press four point probe onto sample, read measured resistance, either let instrument or yourself convert resistance to sheet resistance. Let's say the film was gold (bulk resistivity rho at 300K about 2.2e-6 ohm-cm) and you measure 2ohms/square, then Rsh =rho/t or t=rho/Rsh=(2.2e-6/2) cm  or about 1e-6cm or 10nm (100A). This is simple and quick, and of therefore of course has some issues. Since the mean free path length of electrons in the thin film is on the order of the thickness of the film, a portion of the electrons are reflected (scattered) from the interfaces at the substrate and air, and the actual film resistivity is a bit higher than the bulk (infinite in all directions) resistivity (for gold, correction is about 2.4 vs 2.2e-6ohm-cm). Fuchs and Sondheimer analyzed all of these corrections, but the reality is that a only a rough thickness (within a factor of two) can be obtained because you will never exactly know the mean free path of scattering coefficients to high accuracy.

I have always found e-beam evaporation to be the best method for depositing ultra-thin metal films. By carefully controlling  the beam current , its easy to get a slow enough dep rate and hence a uniform film. I always use the installed and calibrated thickness monitor to predict the thickness of metallic films and compare with ellipsometry. The two values should be close enough but not necessarily the same. Ellipsometry should work for your films as long as their thickness is lower than 100 nm.

If possible, I would prefer a TEM (better HRTEM) analysis, even if it is hardly statistical and the the sample preparation is a bit tedious.

As a follow-up to this discussion, I successfully used a Fischerscope X-Ray XDV-SDD XRF instrument to measure gold films on glass in the 10 to 50 Angstrom range.  I would not say that the method was accurate, but the thickness values were in reasonable agreement with what I expected using a quartz crystal thickness monitor during thermal evaporation.  More importantly, the simple and fast XRF measurements showed that the deposition process was repeatable and that the thickness scaled with deposition time.