Research On The Electrical Characterization Of Sin Thin Films For Solar Cell

The wide use of solar cells will be a feasible way to solve the energy and environmental protection problems. Poly-crystalline silicon solar cells are considered the most promising cells in the future. The application of SiN on poly-crystalline solar cells is the most impotant way to improve efficiency and reduce cost. To achieve this aim, two aspects of poly-crystalline silicon solar cells are studied in this thesis, including the characterization of SiN thin films .SiN thin films were deposited by Plasma Enhanced Chemical Vapour Deposition (PECVD)。Firstly,they were deposited on two batches of Si wafer by the different ratio of [SiH4:N2]/[NH3], deposited temperature and time .the characterization of SiN thin films was studied by spectral ellipsometry, infrared absorption spectroscopy (IR), X-ray Photoelectric Spectroscopy (XPS), quasi-steady state photoconductance decay (QSSPCD) measurements and reflection spectra etc. We have found the best deposition ambient and temperature (the one is [NH3]/ [SiH4:N2]=4:1, deposition temperature is 350℃, time is 8min, the other is temperature is 360℃, SiH4:NH3=5:1, time is 6min ). The secondly, the samples were annealed in N2/ H2 ambience by Rapid Thermal Annealing. The minority carrier lifetime have the Max at 700℃, and hydrogen content have relations with the minority carrier lifetimes. After deposition of SiN films on the poly-crystalline solar cells, the electric current improved greatly and attained an approximate increase of 30%. The increasing amplitudes of the efficiency of solar cells were in excess of 40%.