Energetic Condensation for the Deposition of Polycrystalline Silicon Films on Low Temperature Substrates
Poly-Si thin film transistor (TFT) has better electrical properties than the ones based on amorphous silicon. These TFTs have potential applications in innovative photovoltaics (wearable solar cells) and flexible displays fabricated on plastic substrates. The focus of program is the growth of polycrystalline silicon (poly-Si) on glass and polymer at low temperature by using magnetron-sputtering technique. We have been able to deposit Poly-Si thin films on poly(ethyleneterephthalate) (PET-Mylar) and glass substrates at temperatures as low as 130C. So far, the largest grain size measured by atomic force microscopy is about 95 nm. A number of different techniques such as X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM) and atomic force microscopy (AFM) have been used to study the crystalline structure and surface morphology of films. We study the energetics of the condensation process, particularly the interaction of the growing surface and impinging energetic particles. Various numerical and statistical models are used for this purpose.
K. Xu, A. Pradhan and S. I. Shah, Effect of metal under layers on low temperature silicon growth, J. Appl. Phys. Nov. 1, 2003.
K. Xu, S. I. Shah and D. Guerin, Low temperature deposition and characterization of polycrystalline Si films on polymer substrate, J. Vac. Sci. Technol. A 19, 1078 (2001).
K. Xu and S. I. Shah, Effect of sputtering gas composition on low temperature deposition of polycrystalline silicon films, 44th Society of Vacuum Coaters Annual Technical Conference Proceedings, 33 (2001).