Electrical behaviour of n-type silicon solar cells under reverse bias: Influence of the manufacturing process

This study focuses on the electrical behaviour under reverse bias of industrial n-type crystalline silicon (c-Si) solar cells and particularly on the way the cell manufacturing process impacts this reverse behaviour and breakdown dynamics. Different cell process flows were implemented on n-type Czochralski (Cz) silicon substrates. Corresponding n-type solar cells were then studied by means of reverse current–voltage (I–V) measurements and Reverse Bias Electroluminescence imaging. The breakdown dynamics of our cells was found to differ from one process to another. Three main breakdown behaviours, each assigned to a particular type of defect, have been clearly identified. The limiting type of defect (i.e. the one responsible for the actual cell hard breakdown) was found to depend on the cell manufacturing process. The suppression of the limiting defects was done by means of diamond pin cleavage and allowed us to significantly improve the reverse behaviour of the cells.

► Electrical behaviour of reverse biased n-type silicon solar cells was studied.
► Cells breakdown dynamics differed from one fabrication process to another.
► Cells breakdown sites were imaged: they also depend on process considered.
► We determine which sites are limiting the breakdown behaviour of cells.