Plasma enhanced chemical vapor deposited SiN layers for large area mc-Si solar cell processing

Summary form only given. Surface passivation plays a crucial role in the fabrication process of high efficiency multi-crystalline silicon (mc-Si) solar cells. Plasma enhanced chemical vapor deposition (PECVD) of silicon nitride (SiN) is a proven technique for obtaining layers that meet the needs of surface passivation and anti-reflection coatings. In addition, the deposition process appears to provoke bulk passivation as well due to diffusion of atomic hydrogen. This bulk passivation is an important advantage of PECVD deposition when compared to the conventional CVD techniques. A further advantage of PECVD is that the process takes place at a relatively low temperature of 300/spl deg/C, keeping the total thermal budget of the cell processing to a minimum. This paper deals with the fabrication of multicrystalline silicon solar cells with PECVD SiN layers combined with high-throughput screen printing and RTF firing. Using this sequence we were able to obtain solar cells with an efficiency of 13.5% for multi crystalline polished Si wafers of size 125 mm square. POCl/sub 3/ doped polished silicon wafers with a junction depth of about 0.5 /spl mu/m and an emitter sheet resistance of 35 /spl Omega//sq were selected for the cell fabrication. The mean cell efficiency, fill factor and Voc for the cells prepared in the present study were found to be 13.5%, 0.76 and 0.602 V respectively.