Thin film metallization by supersonic spraying of copper and nickel nanoparticles on a silicon substrate

Copper and nickel nanoparticles are supersonically sprayed onto a silicon wafer to install a low-resistance, high-performance, and cost-competitive front electrode onto a crystalline silicon solar cell. Impact phenomena and the deposition processes of both single and multiple particles were simulated and the computational results were compared against experimental data. Jet formation and local sintering at the particle-to-substrate interface were observed due to adiabatic shear instabilities. Local temperatures increased with impact velocity and estimates of these temperatures were made with a simple energy balance. Multi-particle simulations reveals the processes of thin-film growth; particles are bonded through interfacial sintering that locks the particles into a film. Film plastic strains were highest at the interface and increase risks for delamination.