JOINT RESEARCH AND TECHNOLOGY PROGRAMMES 2004 – 2006

GREECE - CHINA COOPERATION PROJECTS

UNIVERSITY OF PATRAS - UNIVERSITY OF NANAKAI

The main objective of the project is the optimization of Plasma Enhanced Chemical Vapor Deposition (PECVD) of microcrystalline silicon thin films (μc-Si:H) from the deposition rate (> 5 Ǻ/sec) and the % crystalline volume fraction (> 75 %) point of view. This material is used nowadays as an intrinsic layer in thin film photovoltaic solar cells, leading to the increase of the % efficiency of these cells and to more stable operation. The technique that it will be used for the deposition is the Plasma Enhanced Chemical Vapor Deposition (PECVD) through highly diluted silane in hydrogen RF discharges. Special attention will be given to the keep the substrate at very low temperature (< 200 ^οC) in order the process to be compatible for deposition at flexible substrates and to minimize ohmic losses during the application of these films in the cells.  The successive stages of the research effort will be:

·      Optimization of the deposition rate of intrinsic μc-Si:H thin films.  Investigation of the effect of the main process parameters on the film growth rate through non-intrusive plasma diagnostics. 

·      Simulation of the deposition process by using a 2D self – consistent fluid modeling. Study of the μc-Si:H growth mechanism under conditions of low substrate temperature and high deposition rates.  

·      Thin film characterization from microstructure point of view  (% crystalline volume fraction, % fraction of hydrogen in the films and way of bonding)  and for opto-electronic properties.  Optimization of % crystalline volume fraction of the high-rate deposited thin films. 

The successive completion of the stages will lead to the development of a reliable and reproducible process of high – rate deposition of μc-Si:H thin films with high crystalline volume fraction suitable for application in thin film silicon photovoltaic solar cells.
 

Start Date: 2005-01-01

End Date: 2006-12-31

Duration: 36 months

Project Status: Completed