Investigation of barrier layers on ceramics for silicon thin film solar cells

Crystalline silicon thin films solar cells made by high temperature deposition on foreign substrate have the potential for reducing the cost through material consumption. The draw-back could be the possible migration of impurities from the substrate to the active layer. Here we investigated the diffusion of contaminants from ceramic substrates, namely mullite and SiAlON using the Deep Level Transient Spectroscopy (DLTS) technique as indirect method of impurity detection in silicon. We have identified Mg, Mn and Fe as the main contaminants. We have also shown that coating the ceramics with ONO or SOG layers reduces drastically the impurities concentrations in silicon. These layers are therefore efficient barrier layers.