결정질 실리콘 태양전지를 위한 실리콘 질화막의 특성
Properties of Silicon Nitride Deposited by RF-PECVD for C-Si solar cell
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Silicon nitride(SiNx:H) deposited by radio frequency plasma enhanced chemical vapor deposition(RF-PECVD) is commonly used for anti-reflection coating and passivation in crystalline silicon solar cell fabrication. In this paper, characteristics of the deposited silicon nitride was studied with change of working pressure, deposition temperature, gas ratio of NH3 and SiH4, and RF power during deposition. The deposition rate, refractive index and effective lifetime were analyzed. The (100) p-type silicon wafers with one-side polished, 660-690μm, and resistivity 1-10 Ω·㎝ were used. As a result, when the working pressure increased, the deposition rate of SiNx was increased while the effective lifetime for the SiNx-deposited wafer was decreased. The result regarding deposition temperature, gas ratio and RF power changes would be explained in detail below. In this paper, the optimized condition in silicon nitride deposition for silicon solar cell was obtained as 1.0 Torr for the working pressure, 400 °C for deposition temperature, 500 W for RF power and 0.88 for NH3/SiH4 gas ratio. The silicon nitride layer deposited in this condition showed the effective lifetime of >1400 μs and the surface recombination rate of 25 cm/s. The crystalline silicon solar cell fabricated with this SiNx coating showed 18.1% conversion efficiency.
Abstract
Silicon nitride(SiNx:H) deposited by radio frequency plasma enhanced chemical vapor deposition(RF-PECVD) is commonly used for anti-reflection coating and passivation in crystalline silicon solar cell fabrication. In this paper, characteristics of the deposited silicon nitride was studied with change of working pressure, deposition temperature, gas ratio of NH3 and SiH4, and RF power during deposition. The deposition rate, refractive index and effective lifetime were analyzed. The (100) p-type silicon wafers with one-side polished, 660-690μm, and resistivity 1-10 Ω·㎝ were used. As a result, when the working pressure increased, the deposition rate of SiNx was increased while the effective lifetime for the SiNx-deposited wafer was decreased. The result regarding deposition temperature, gas ratio and RF power changes would be explained in detail below. In this paper, the optimized condition in silicon nitride deposition for silicon solar cell was obtained as 1.0 Torr for the working pressure, 400 °C for deposition temperature, 500 W for RF power and 0.88 for NH3/SiH4 gas ratio. The silicon nitride layer deposited in this condition showed the effective lifetime of >1400 μs and the surface recombination rate of 25 cm/s. The crystalline silicon solar cell fabricated with this SiNx coating showed 18.1% conversion efficiency.
참고문헌 (10)
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