Résumé
•Ablation of Al2O3 and Al2O3/SiNx on Si substrates was performed with a nanosecond UV laser.•Ablation thresholds were found in good agreement with COMSOL simulation, around 0.85 and 0.95Jcm−2 for Al2O3 and Al2O3/SiNX, respectively.•Laser-induced damage was evaluated at room temperature by time-resolved photoluminescence decay with a single photon counting detector.•Minority carrier lifetime in silicon as a function of the ablation fluence was derived from the photoluminescence decay and related to the thickness of the heat affected zone.•Quantitative measurements of laser-induced damage can be used to evaluate laser ablation of dielectrics in photovoltaics.
Selective laser ablation of dielectric layers on crystalline silicon wafers was investigated for solar cell fabrication. Laser processing was performed on Al2O3, and bi-layers Al2O3/SiNX:H with a nanosecond UV laser at various energy densities ranging from 0.4 to 2Jcm−2. Ablation threshold was correlated to the simulated temperature at the interface between the dielectric coatings and the silicon substrate. Laser-induced damage to the silicon substrate was evaluated by time-resolved photoluminescence. The minority carrier lifetime deduced from time-resolved photoluminescence was related to the depth of the heat affected zone in the substrate.