Thin Film Characterization by Rutherford Backscattering (RBS) as a Strong Complement to Our Current Research Efforts
EMSL Project ID
33224
Abstract
In my group at BYU and through my past research we have a great deal of experience in modification of substrates with thin films, including monolayers, polymeric coatings, and sputtered films. We desire to have access to the Rutherford Backscattering accelerator at PNNL because it will strongly complement our current research efforts. We have three manuscripts being written right now that would benefit from RBS data. One is on silane modification of Si/SiO2 substrates. This paper is a unique exploration of the gas phase deposition of three related silanes, including a study of their deposition conditions, surface stability, density of functionality, and response to a cyanine dye. Another is on the modification of hydrogen-terminated silicon with polybutadiene, where this polybutadiene is modified, both before and after adsorption, by thiol-click-chemistry. This appears to be the first report of functionalization of this important surface with an intact polymer, where the thiol-click-chemistry adds a unique twist to the work. In a third manuscript, we are exploring new write layers for optical data storage devices. That is, we have developed a new write layer for optical data storage that appears to give this medium tremendous longevity. In the first project, RBS would give us absolute quantitation of the degree of surface reactions, which is information that is difficult to obtain by other methods. In particular, amine-modified substrates would undergo reactions that would introduce heavy atoms at their surfaces. These atoms could be accurately detected and quantified by RBS. The resulting samples could then be used as standards in XPS, which would allow us to very accurately quantify other lighter atoms. RBS would also allow us to estimate the concentrations of the lighter atoms, e.g., N, C, and O, on the heavier substrate, Si, although this situation is less than ideal for RBS. RBS would provide us with the same information for the second manuscript, giving us exact numbers of sulfur atoms on our silicon surfaces. Sulfur is ideal for RBS in this project because it is the heaviest atom in our films/substrates. In the third project, RBS would give us both depth profiles and exact numbers of species in our thin films. Here we have heavier atoms on a lighter polycarbonate (carbon, oxygen, and hydrogen) substrate. We do have access to XPS, ToF-SIMS, optical ellipsometry, wetting, and AFM at our home institution, and these techniques are genuinely useful for surface characterization. However, in many, if not most situations, none of them is as inherently quantitative as RBS in providing accurate surface compositions, nor can these methods provide depth profiles with the same ease. Hence we desire to have this additional information to advance our research through a collaboration at the EMSL facility.
Project Details
Project type
Limited Scope
Start Date
2009-07-22
End Date
2009-09-21
Status
Closed
Released Data Link
Team
Principal Investigator