ABSTRACT
This chapter demonstrates that the high stress can be correlated to the accumulation of carbon in the twin boundaries by a combination of transmission electron microscopy, high resolution electron microscopy, energy dispersive X∼ray analysis and image simulation. The experimental results will be compared with ab-initio structure simulations of the energy relaxation due to incorporated carbon. Multicrystalline silicon is a low-cost material for photovoltaic applications. Wafers of are produced by different techniques such as ingot casting, Tri-crystal growth or ribbon growth. The Edge-defined film-fed growth (EFG) technique belongs to the latter method and is attractive since it allows wafer production of high quality with a large output and low costs. Macroscopically, EFG wafers are characterized by high local mechanical stresses, which are up to five times higher than in other mc-Si materials. Topographic stress measurements of the EFG-wafer revealed regions with high local internal stress correlating with a high density of twin lamellae.
