Deep level defects in oxygen doped EFG poly-Si

There is considerable current interest in polycrystalline silicon and the edge-defined film-fed growth (EFG) technique is a suitable candidate for low-cost solar cell production. Recently, it has been shown that oxygen addition during the crystal growth yields higher efficiency solar cells. We studied deep levels associated with structural defects like dislocations and grain boundaries, and the influence of oxygen addition to the bulk on the picture of deep levels in the material. We have shown that levels attributed to dislocations are directly influenced by oxygen addition. We have also found that such levels originate predominantly from grain boundaries and to lesser extent from intragrain regions.