Mostly ceramic substrates (MgO, STO, LaAlO3 etc..) are used to deposit transition Metals (Pt,Ag,Au,Cu) for the electrochemical applications. Why Silicon Substrate can not be used for such applications?
Hello,
Pt like many other metals is forming silicides on top of silicon. So there is inter-diffusion which leads to other behavior.
Have a nice day
Dietmar
No Dietmar, Pt has lower Oxygen affinity, how it can form a inter-diffusion layer with Silicon???
We always need a very thin buffer layer (Ti) in case of thick film metals (Au, Pt, Ag, Cu,...) deposited over Si (or un-functionalized SiO2 / Si) wafers. Otherwise, there is no (chemical, dispersive, diffusive) adhesion[1] on Si wafers, as substrates at room temperature. At high substrates' temperature, metals might easily diffuse in the bulk, as Dietmar Hirsch, having, also, no good mechanical adhesion, compared to the standard buffer layer (Ti).
1. https://en.wikipedia.org/wiki/Adhesion
Hello all,
Pt is quite an exemption: different from e.g. Au, it does not diffuse but rather acts as a diffusion barrier. And it adheres very well if sputtered (no experience about PVD} - also on SiO2 and Si3N4. Sometimes this comes really versatile. Pd should be similar.
Regards
Quotation (Dreher): "e.g. Au, it does not diffuse but rather acts as a diffusion barrier",
e.g. isolated Au (not on Si, but) on the Si oxide layer. So, an electrically isolated (Au, Pt, Ag, Cu) layer would be NOT (among other stability issues) very useful for "electrocatalytic applications" : this is the initial question of Ali Hassan Kazmi. The buffer layers is an important step to accomplish a successful eutectic bonding on Si wafers as a potential alternative electrode (e.g. NOT el. isolated) for electrochemical applications.
@Ioannis Samaras.. Some research group uses Ni as the Seed layer to deposit Pt, But on MgO substrates.
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