Efficiency potential of P-type Al2O3/SiNx passivated PERC solar cells with locally laser-doped rear contacts

Technological restrictions on the screen-printed rear-contact feature size on the order of 100 mm are among the limiting factors of the efficiency of p-type passivated emitter rear-contact (PERC) solar cells. Simultaneous contact opening and doping using localized laser processing can overcome these design limitations. We use 3-D numerical device simulations to show that an efficiency gain of 0.3%abs compared with a screen-printed baseline cell, is possible if laser-formed point contacts of 5 mm in size with a contact recombination parameter of 5000 fA·cm-2 and a contact resistance of 10-4 O·cm2 are used. We experimentally demonstrate the implementation of simultaneous rear-surface contact opening and doping on large-area 156 × 156 mm2-sized PERC solar cells using ultraviolet (UV) and green laser systems. We achieve efficiencies of up to 19.9% for this process with a 10-nm atomic layer deposited Al2O3/80-nm plasma-enhanced chemical vapor deposited SiNx rear-surface dielectric stack.