Criteria for choosing a substrate for thin films

In summary, the criteria for choosing a substrate to deposit thin films depend on the type of growth desired. For epitaxial growth, the substrate's crystal structure and lattice constants should match the film being deposited. For liquid on solid deposition, the substrate's surface should be either hydrophobic or hydrophilic depending on the solvent. In general, clean and flat surfaces are preferred for physical deposition methods. Many articles may choose silicon as a substrate due to its availability, unless epitaxial growth is necessary.
  • #1
ralden
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Hi guys!, i want to know what are the criteria in choosing a substrate to deposit thin films, like what are the physical and chemical properties of the substrate to be compatible in depositing thin films?
 
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  • #2
ralden said:
Hi guys!, i want to know what are the criteria in choosing a substrate to deposit thin films, like what are the physical and chemical properties of the substrate to be compatible in depositing thin films?

If you are aiming for epitaxy, then the crystal structure and lattice constants of the substrate should be similar to the film you are depositing.
if you want a liquid on a solid then the surface should be hydrophobic or hydrophilic depending on if the solvent is nonpolar or polar.

Using physical deposition, such as e-beam evaporation, you can deposit just about anything on anything else.
Generally you want very clean, flat surfaces.
Also look up sputtering, CVD, PECVD, MOCVD, PVD, etc.
 
  • #3
Hyo X said:
If you are aiming for epitaxy, then the crystal structure and lattice constants of the substrate should be similar to the film you are depositing.
if you want a liquid on a solid then the surface should be hydrophobic or hydrophilic depending on if the solvent is nonpolar or polar.

Using physical deposition, such as e-beam evaporation, you can deposit just about anything on anything else.
Generally you want very clean, flat surfaces.
Also look up sputtering, CVD, PECVD, MOCVD, PVD, etc.

I want to deposit ZnO (n-type) thin films in Silicon (p-type) substrate using spray pyrolysis, but i don't know the reasons why many articles choose silicon over other substrates
 
  • #4
if not for epitaxial growth, then i would guess availability.
 

1. What is the importance of choosing the right substrate for thin films?

The substrate plays a crucial role in determining the properties and performance of thin films. It provides mechanical support and can influence the adhesion, crystallinity, and surface morphology of the film. Therefore, choosing the right substrate is essential for the successful fabrication of thin films.

2. What are the main criteria for selecting a substrate for thin films?

The main criteria for choosing a substrate for thin films include its compatibility with the deposition technique, chemical and thermal stability, surface roughness, and cost. It should also have a similar coefficient of thermal expansion as the thin film material to prevent cracking or delamination.

3. How does the substrate material affect the properties of thin films?

The substrate material can significantly affect the properties of thin films. For example, a highly conductive substrate can improve the electrical conductivity of the thin film, while a transparent substrate can allow for the transmission of light through the film. The choice of substrate can also impact the growth kinetics and crystal structure of the thin film.

4. Can any material be used as a substrate for thin films?

No, not all materials can be used as a substrate for thin films. The substrate material should have a high melting point, be chemically inert, and have a smooth and flat surface. It should also be compatible with the deposition technique and the intended application of the thin film.

5. How does the substrate preparation affect the quality of thin films?

The substrate preparation is crucial for the quality of thin films. It involves cleaning, surface treatment, and annealing to remove any impurities or contaminants that can affect the film's properties. Proper substrate preparation can improve the adhesion, density, and uniformity of the thin film, resulting in a better quality product.

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