I thought it is possible to reduce the interface mismatch (strain) between the film and the substrate by introducing the step structure. The steps due to the miscut could be served as a misfit accommodation step (structure ledge or disconnection). If the proper miscut angle is applied, a singular interface could be formed.

Ref (1): One of the potentially optimal interfaces of β-FeSi2/Si, at http://www.sciencedirect.com/science/article/pii/S0022024805002010

(2)The Origin of Local Strain in Highly Epitaxial Oxide Thin Films http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3813935/?report=classic

Because the steps on a vicinal surface are more controlled and are in general more favorite nucleation sites. In practice a non-vicinal substrate has some local variation in flatness which can cause steps spacing between 10 µm and 10 nm (depending on polish substrate etc.)

And as mentioned certain step structures could help to stabilise a certain phase (e.g. Si (001) A and B steps for growth of polar on non-polar).

Reducing the mismatch would mean that the film on top is tilted with respect to the underlying surface. That would require a very fine adjustment taking into accout also the thermal expansion at deposition temperatures.

In some instances miscut substrates are used because the distance between the atomic steps is shortened. This has advantages in terms of the adatom migration of species on the surface. i.e. if the migration distance is greater than the step distance, two dimensional epitaxial growth is more likely to occur; if the migration distance is less than the step distance three dimensional polycrystalline growth is likely to occur.

Thank you all, gentlemen!

Initiate nucleation on the foreign substrate.

Steps serve as nucleation sites and release strain, in addition you will have a preferential growth direction and this may reduce the formation of twins or domains for systems with different symmetries, (GaAs (111) and CuInSe2(112).

Dear Mikhail Lovygin,

In comparison with low index Si(001) or Si(111) substrate, when high index Si(553), Si(557), Si(5 5 12) substrates are reconstructed followed by flash heating  in UHV, they consist of step-terrace like structure. On such template, when thin films are grown, metal ad-atoms are comprised of higher mobility along the step-edge direction. For example, on reconstructed Si(5 5 12) substrate, Ag adatoms exhibit higher mobility along  Si(1-10) in comparison to Si(66-5). Therefore such templates are potentially used for fabrication of one dimensional metallic nanostructures. Indeed, I have extensively studied various morphologial and structural aspects of AuAg bimetallic growth on reconstructed high index Si(hkl) substrates.

Hopefully, my answer will be useful for you.

With regards

Anjan