Laser doping using phosphorus-doped silicon nitrides

Abstract

Phosphorus-doped silicon nitride (SiN(P)) layers have been investigated as dopant sources for laser-induced diffusion. Their optical properties were measured and revealed that reflectivity and refractive index were weakly affected by adding phosphorus (P) and that SiN(P) layers could consequently be used as anti-reflection coatings. These layers were also found to offer efficient surface passivation regardless of the introduced P quantity. Laser doping (LD) and thermal annealing (TA) were then carried out and showed that a wide doping range can be obtained from SiN(P) layers using both driving-in methods. Selective emitter solar cells were then processed using TA to realize the thin emitter and LD to pattern the heavily-doped areas to be metalized. Though cells results need to be further improved, SiN(P) layers appear to be extremely promising as dopant sources for low-thermal budget selective emitter solar cells processing.