Growth of stable dislocation-free 3-grain silicon ingots for thinner slicing

Using the CZ technique we have set up a 3-grain silicon ingot growing process which allows to obtain very large grains with a preselected orientation in order to facilitate thin slicing, a unanimously agreed upon requirement for photovoltaic applications. The 3-grain ingots we obtained are particularly suitable for this aim since no cleavage plane {111} crosses the crystal obliquely to the slicing direction. Furthermore, this type of ingot allows a high growth rate ascribable to the verticality of its {111} side planes and has electrical and structure properties very close to those of single-crystalline material.