Interdiffusion and Thin-Films Lab
We study metal alloys and thin layer films.
A variety of methods are used to prepare the samples studied in the lab. The equipment and procedures are complex, but we will give a brief overview of them.
- Splat-quenching: This is a method used to obtain amorphous metal compounds for study. This was last used to study Ir (iridium) Zr (zirconium) compounds. Beginning with a totally amorphous sample, we can measure the heats of crystallization assured that there was no previous crystal structure that would alter the measurements for the change. These accurate measurements for the crystallization of these compounds provides new, empirical knowledge.
- Sputtering: This process is a way to form thin films of substances on a substrate. By bombarding what is desired in the coat with ions, some of the surface is freed and then deposited on the substrate.
- Thermal evaporation: This is much like the sputtering. Only instead of bombarding a surface to knock molecules off, a sample (with a low enough melting point) is boiled in a vacuum. Since it is in such low pressure, it readily vaporizes and can be deposited on a substrate. While sputtering can be used with almost anything, this does require the sample to have a low melting point (copper, tin, etc).
- E-beam gun evaporation: Electron beam gun evaporation is an efficient way of evaporating a source material and allowing for thin film coatings upon a substrate. It can achieve temperatures in excess of 3500oC, works in an ultra-high vacuum, and can evaporate most materials (i.e. refractory, dielectric, magnetic, and conductive). This allows for easy formation of clean, thin film coatings. This is a new acquisition by the department, and more information will soon be added.
How our samples are investigated
- The DSC (Differential Scanning Calorimeter): This is used to obtain thermodynamic and kinetic data (enthalpies of formation, reaction constants, diffusion coefficients, etc.) for the formation of different alloys and intermetallic compounds that are studied by members of the PVD lab. Binary systems that are currently of interest are M-Sn alloys ( M= Cu, Ni, Pd, Au), M-Zr alloys (M= Ni, Pd, Ir), and many different silicides(link missing ), including Cu-Si, Co-Si, Ti-Si, Fe-Si and Ni-Si.
- X-Ray Diffraction(link missing ): This is used to determine the state of a prepared sample. If there was any crystal or intermetallic growth during the initial sample preparation, this can detect that as well as any impurities (ie, oxides). If you are familiar with x-ray crystallography, this should sound similar.
- Optical Microscopy(link missing ): Just like it sounds, this is the simple microscopy you remember from your science kit when you were 12 years old. Magnified up to 1000x, the samples are visually judged.
- Scanning Electron Microscopy (SEM)(link missing ): This is used to characterize both the reacted samples and the prepared. Using electrons rather than light waves, the surface of the sample is studied.