Effect of Superimposed DC Power on the Properties of Intrinsic Hydrogenated Amorphous Silicon Passivation Layer Deposited by RF Facing Target Sputtering

Radio frequency facing target sputtering (RF-FTS) has a potential to deposit high-quality intrinsic hydrogenated amorphous silicon (i-a-Si:H) passivation layers for silicon heterojunction (SHJ) solar cells without using hazardous gases. We investigated the effect of superimposed dc power on the deposition of i-a-Si:H by RF-FTS to improve the deposition rate. The i-a-Si:H layer deposited by dc-superimposed RF-FTS showed higher passivation quality and higher deposition rate compared to the i-a-Si:H layer deposited by RF-FTS. A low surface recombination velocity of 7.7 cm/s and a deposition rate of 6.8 nm/min were achieved by adopting dc-superimposition. An SHJ solar cell fabricated using a flat substrate and passivated with the i-a-Si:H layer deposited by dc-superimposed RF-FTS showed a conversion efficiency of 16.9%.