Low temperature SiNx:H films deposited by inductively coupled plasma for solar cell applications

Amorphous hydrogenated silicon nitride thin films with different chemical compositions (SiNx:H) have been synthesized by using low frequency inductively coupled plasma of Si + N2 + H2 at a low temperature of 100 °C. The bonding configurations, bond density, hydrogen content, and chemical composition, as well as the refractive index are intensively investigated by a variety of characterization tools. Silicon nitride based antireflection layer on alkaline-textured silicon surface reduces the reflectivity to about 4%. As-deposited silicon nitride films exhibit an excellent passivation effect on p- and n-type Si. The surface recombination velocity is reduced to 36 cm/s on n-type silicon with resistivity of 2–3 Ω cm. The passivation effect originates from the H-related chemical passivation and fixed charge related field passivation. The growth mechanism of SiNx:H from the precursor gas of H2 diluted mixture of silane and nitrogen is also discussed.