A method for industrial characterisation of crystalline silicon wafers

We propose a method for an industrial characterisation of silicon wafers using a contactless photoconductance instrument. The main difficulty is given by the characteristics of commercial Si wafers for PV in terms of lifetime and doping level. In our method we perform extraction of effective lifetime at all the injection levels we obtain. The shape of effective lifetime vs. injection level curve depends on both the material characteristics and the processing technology employed. We have found a good correlation between the wafer curve shape and the final characteristics of the solar cell obtained. The principal goal of the method is to enlarge the use of the contactless photoconductance instrument to industrial characterisation and to have a method that can calibrate each processing step for the maximum efficiency.