Laser ablation of antireflection coatings for plated contacts yielding solar cell efficiencies above 20 %

To reduce shadowing losses and therefore gain higher short current densities JSC as well as to overcome contact resistance limitations a front side metallization based on laser ablation of the antireflection coating and plated contacts is proposed. In this paper we will present solar cells with efficiencies of up to 20.7 % featuring an industrially feasible shallow diffused 110 Ohm/sq. emitter and a plasma enhanced chemical vapour deposition (PECVD)-SiN antireflection coating. The main focus in this paper lies on the laser ablation process. The characteristics of ns- and ps-laser ablation regarding the influence on the emitter profile and the ablation pattern on a textured surface will be discussed.