Preparation of hydrogenated amorphous silicon carbon nitride films by hot-wire chemical vapor deposition using hexamethyldisilazane for silicon solar cell applications

We propose hydrogenated amorphous silicon carbon nitride (a-SiCN:H) films prepared by hot-wire chemical vapor deposition (HWCVD) using hexamethyldisilazane (HMDS) as a new passivation layer of silicon solar cells. The films deposited at various deposition conditions were characterized focusing on optical properties and passivation quality. We found that the effective lifetime of the samples depended on the amount of Si-H bond and had strong correlation with the interface trap densities. After the optimization, the effective surface recombination velocity of n-type single crystalline silicon (c-Si) (1-10 Ω cm) with a-SiCN:H films has become lower than 60 cm/s and that of p-type was approximately 300 cm/s. The efficiency of a cast polycrystalline silicon solar cell using a-SiCN:H as a passivation layer reached 13.7% (2 × 2 cm). Experimental results indicate that a-SiCN:H films are promising low-cost antireflection and passivation layers for silicon solar cells. © 2007 The Japan Society of Applied Physics.