Simplified fabrication of n-type Cz-Si HIP-MWT+ solar cells with 20% efficiency using laser structuring

We present 6-inch n-type Cz-Si metal wrap through (MWT) solar cells with screen-printed and fired contacts achieving energy conversion efficiencies of 20%. In order to decrease the occurrence of leakage currents under forward operation to a minimum after applying reverse bias load, the structuring of the rear side phosphorus doping in the area of the external p-type contacts is necessary. The fabrication of these so-called n-type high-performance MWT+ (n-HIP-MWT+) solar cells is considerably simplified by using laser processes to locally structure the rear side phosphorus doping. The n-HIP-MWT+ cells fabricated with laser structuring achieve the same peak energy conversion efficiency of 20% as conventionally fabricated ones, which are manufactured using an elaborate inkjet-based masking process prior to phosphorus diffusion. The loss of cell efficiency after reverse biasing is decreased to - 0.1%abs independent of the structuring method, and is three times smaller than the one observed for cells without structuring of the phosphorus doping.