Articles
  • Computer Simulation and Experimental Study on the Casting of Polycrystalline Si Wafer by Vacuum Casting Method 
  • G.H. Lee*, S. Aukkaravittayapuna,c, J.S. Shinb, Z.H. Leeb and K.S. Lima
  • Nuclear Materials development team, Korea Atomic Energy Research Institute, 150 Dukjindong Yusonggu Daejeon 305-600, Korea a Department of Electrical Engineering and Computer Science, Korea Advanced Institute of Science and Technology, 373-1 Gusongdong, Yusonggu, Daejeon 305-701, Korea b Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology, 373-1 Gusongdong, Yusonggu, Daejeon 305-701, Korea c National Metal and Materials Technology Center (MTEC), National Science and Technology Development Agency, 114 Paholyothin Rd., Klong 1, Klong Luang, Pathumthani 12120 Thailand
Abstract
A vacuum casting method was attempted to produce cheap poly-Si wafers ready for solar cell fabrication without any cutting or slicing. However, the 5 × 5 cm2 lab scale cast poly-Si wafers contained high carrier concentrations, above 3 × 1017/cm3, and crystalline defects like grain boundaries and gas porosity. We carried out a set of vacuum casting experiment in order to identify the main sources of impurities during vacuum casting and investigated the impurities in the cast poly-Si wafers. The efficiency of the test solar cells fabricated on the cast poly-Si wafers was below 1.0% whereas the efficiency of the solar cell fabricated on the wafer sliced from starting Si was 5.5%. The low efficiency of the test cells was attributed to high carrier concentrations and gas porosity inside the cast poly-Si wafer.

Keywords: vacuum casting, polycrystalline silicon, solar cells, impurities, gas porosity

This Article

  • 2003; 4(3): 126-130

    Published on Sep 30, 2003