Kerf-free wafer slicing and thinning for semiconductor applications

The waste of valuable raw material due to kerf-loss during manufacturing of wafers is an important problem not only in photovoltaics but also in the semiconductor industry in general. Although a number of kerf-free wafering methods have been developed over the past decades they have not found significant use outside of the PV industry, due to some inherent shortcomings of those methods. Recently, we have been able to achieve a major step forward in this regard. In this paper we present a novel kerf-free technology that is able to overcome the main limitations of existing kerf-less wafering methods that have prevented them from being adopted in semiconductor applications outside of the PV sector. In particular, we demonstrate that the Siltectra-Method (i) can produce wafers from a range of materials commonly used in semiconductor applications, such as Si, Ge, GaAs, SiC, etc, at the required diameters (currently up to 300mm wafers have been successfully manufactured), with the appropriate crystal orientations, (ii) that it can also produce wafers with thicknesses in the range required by semiconductor applications (which are generally thicker than in PV), and (iii) that it can potentially even be used as a material-saving alternative to many wafer thinning applications. As a proof-of-concept example we use our method for manufacturing full size solar cells and panels having the same performance as reference cells but requiring 25% less feedstock material. Furthermore, our cells show an average conversion efficiency of 17.4%, which to the best of our knowledge is the highest efficiency reported for any solar cell produced by kerf-less wafering methods so far.