Scanning thin film processing

Figure 4.7. Contact-mode AFM surface and line-profile scans of a 148-nm A1PO film on Si after a 1000 °C anneal for 5 min. [Reproduced with permission. Meyers, S. T. Anderson, J. T. Hong, D. Hung, C. M. Wager, J. F. Keszler, D. A. 2007. Solution processed aluminum oxide phosphate thin-film dielectrics. Chem. Mater. 19 4023 1029. Copyright 2007 American Chemical Society.]...

FIGURE 10.13b. Raman measurements of the SiNW thin film on the Mylar thin film, except the sample was scanned to maximize the peak at 520 cm . This shows that the sample may contain crystalline chips carried over during the removal process. 

Thin layer concepts may also be involved in metal deposition into thin films of mercury during stripping analysis, in (electro)chemical processes in adsorbates, films or precipitates on modified electrodes, or in scanning electrochemical microscopy. 

FIGURE 27.6 Scanning electron microscope photomicrographs of representative microstructures of (a) PZT and (b) BT thin films on platinum prepared by a chelate process. 

This paper describes ongoing studies of the electrodeposition thin films of the compound semiconductors CdTe and InAs, using the method of electrochemical atomic layer epitaxy (ALE). Surface limited electrochemical reactions are used to form the individual atomic layers of the component elements. An automated electrochemical flow deposition system is used to form the atomic layers in a cycle. Studies of the conditions needed to optimize the deposition processes are underway. The deposits were characterized using X-ray diffraction, scanning probe microscopy, electron probe microanalysis and optical/infrared absorption spectroscopy. 

To obtain TRIR spectra with sufficient sensitivity, we typically signal average several thousand laser shots at each IR frequency of interest. A flow cell, therefore, is necessary to prevent excessive sample decomposition, especially when photo-irreversible processes are monitored. A reservoir of solution (typically 10-20 mL) is continually circulated between two calcium or barium fluoride salt plates. To maintain sample integrity for non cyclic systems, one is usually forced in the dispersive TRIR experiment to acquire data in a series of short (e.g., 100-200 cm ) scans rather than in one complete scan. Thus, a substantial amount of sample may be required. Sample integrity is also of significant concern in the step-scan FTIR experiment because data must be collected at each mirror position. To address this concern, very large reservoirs of solution are required alternatively, a sample changing wheel [33] or very focused pump-probe beams in combination with sample translation [34] have been used with thin film samples. 

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