ITO/SiOx:H stacks for silicon heterojunction solar cells

A method of reducing optical losses in the transparent conductive oxides (TCO) used in silicon heterojunction solar cells without compromising with series resistance is described. In the method the thickness of a TCO is reduced two-three times and a hydrogenated dielectric is deposited on top to form a double layer antireflection coating. The conductivity of a thin TCO is increased due to the effect of hydrogen treatment supplied from the capping dielectric during the post deposition annealing. The optimized cells with ITO/SiOx:H stacks achieved more than 41 mA/cm2 generation current on 120-micron-thick wafers while having approximately 100 Ω/square sheet resistance. The paper also considers integration of ITO/SiOx:H stacks with Cu plating and using ITO/SiNx/SiOx triple layer antireflection coatings.