Advanced surface passivation of crystalline silicon for solar cell applications

Abstract

Excellent passivation of the front and rear surfaces is key for achieving higher efficiency of crystalline silicon (c-Si) wafer solar cells. This thesis presents significantly improved surface passivation results for dynamically deposited plasma silicon nitride (SiNx?) films, to levels which previously were only possible with static depositions. If applied to the front of n+p solar cells, these films are shown to improve the cell efficiency by up to 0.2% absolute. Furthermore, excellent c-Si surface passivation is developed using SiOx/SiNx stacks, whereby the SiOx is deposited using a plasma or a wet-chemical method. In addition, excellent passivation of both n+ and p+ c-Si surfaces with a large range of sheet resistances is established using industrially fired plasma AlOx or stacks. The SiNx, SiOx/SiNx and AlOx/SiNx films and stacks developed in this work are applied on the rear of p-type Si solar cells and are shown to significantly improve the cell efficiencies.