Paper EN-ThP11
Low-Damage Deposition of Thin Silicon Films for Solar Panel Production using Surface-Wave Plasma Source

Thursday, November 1, 2012, 6:00 pm, Room Central Hall

An innovative kind of plasma source for the deposition of thin silicon films used in semiconductor manufacturing is currently under development at Starfire Industries LLC and CPMI Center for Plasma Material Interaction, University of Illinois Urbana Champaign. The source, operating in the microwave range, is able to efficiently generate high-density and low-electron-temperature SiH4-H2 plasmas, and can easily be scaled upward to the deposition of thin films on large-area surfaces. The silicon films deposited at low RF power on glass substrates have been characterized using multiple techniques, comprising SEM, Ellipsometry and Raman Spectroscopy. Spectroscopic data in the UV-VIS-NIR range have been acquired during the discharge operations for plasma characterization. By using Raman spectroscopy, the crystalline volume fraction of the deposited films has been obtained for several input mass-flows of silane, as a function of the substrate temperature and for several pressures of the Hydrogen gas. The averaged film growth rate has been obtained from both ellipsometry measurements and SEM imaging. From the results of the preliminary characterization, the possibility to obtain low-damage growth of a-Si:H and nc-Si:H thin films has been assessed. The trend of the crystallinity as a function of the electron temperature has also been presented, and its relationship with the low potential-drop allowed by this source at plasma-substrate interface has been discussed.