Passivation of solar cell emitters using aluminum nitride

Layers of hydrogenated aluminum nitride have proven excellent passivation properties on lowly doped silicon. Effective surface recombination velocities below 8 cm/s have been reached due to a very low interface defect density. In this work, the passivation of highly doped silicon is studied by measuring the emitter saturation current of boron as well as phosphorous emitters. It is shown that hydrogenation is a prerequisite for reaching effective passivation. Emitter saturation current densities of around 100 fA/cm² are presented for highly doped p⁺-type and n⁺-type silicon allowing maximal open circuit voltages of ~680 mV for silicon solar cells.