Thin films controlling morphology

These model compounds can also be used in device fabrication, since thin films of appropriate thickness can be obtained by sublimation and subsequent deposition onto a substrate in vacuum. Electrical as well as optical properties of such devices have turned out to be strongly dependent on both the molecular packing within the crystallites and the polycrystalline morphology. Understanding and control of this aspect is one of the current scientific challenges. 

The work described here is concerned with the development of electrochemical methodologies to grow compound semiconductors with nanoscale or atomic layer control. That thin-films of some compounds can be formed electrochemically is clear. The questions are how much control over deposit composition, structure and morphology can be obtained What compounds, and of what quality, can be formed ... 

Hoffmann, S. Waser, R. 1999. Control of the morphology of CSD-prepared (Ba,Sr)Ti03 thin films. I. Euro. Ceram. Soc. 19 1339-1343. 

Jamil, E., et ah, Electrodeposition of gold thin films with controlled morphologies and their applications in electrocatalysis andSERS. Nanotechnology, 2012. 23(25) p. 255705. 

One of the major benefits of the ECALE methodology is that it breaks compound electrodeposition into a series of identical cycles and each cycle into a set of individual steps. Each step is examined and optimized independently, resulting in increased control over deposit structure, composition, and morphology. Better understanding of the individual steps in the deposition mechanism should allow the electrochemical formation of high-quality thin films of compound semiconductors. 

Thin films of phthalocyanine compounds in general, and those prepared by the LB method in particular, display novel electrical properties (Baker, 1985). The LB technique for depositing mono- and multilayer coatings with well-controlled thickness and morphology offers excellent compatibility with microelectronic technology. Such films have recently been reviewed for their potential applications. The combination of LB supramolecular films with small dimensionally comparable... 

General Process Considerations. To be useful, a CVD process must produce thin films with reproducible and controllable properties including purity, composition, film thickness, adhesion, crystalline structure, and surface morphology. The growth rates must be reasonable, and the deposition must not have significant impact on the microstructures already formed in the substrate. The deposition time must be sufficiently short, and the temperature has to be low enough so that dopant solid-state diffusion does not smear the results of previous processing steps. 

---