The Study of Silane-Free SiC[sub x]N[sub y] Film for Crystalline Silicon Solar Cells

Abstract

We deposited plasma-enhanced chemical vapor deposition silicon carbon nitride ͑SiC x N y ͒ antireflection coating and passivation layers using a silane-free process. We used a solid polymer source developed at SiXtron Advanced Materials to eliminate the storage and handling of dangerous pyrophoric silane gas. We used ammonia flow rate as a control for the chemical and optical properties in the silane-free process. As NH 3 flow rate increases, the carbon content, refractive index, extinction coefficient, and surface charge density of the film decrease. At an ammonia flow rate of 3000 sccm, which is similar to the conventional SiN x , the extinction coefficients for the two films were similar. This led to an emitter dark saturation current density ͑J oe ͒ of 404 fA/cm 2 for the two films on 45 ⍀/ᮀ emitters. However, a stack passivation of SiO 2 /SiC x N y on an 80 ⍀/ᮀ emitter resulted in an emitter dark saturation current density of 95 fA/cm 2 , which is enough to provide a good surface passivation for high efficiency solar cells. An energy conversion efficiency of 17.4% was obtained for a 149 cm 2 textured Czochralski screen-printed solar cell with this stack passivation. For a 156 cm 2 nontextured multicrystalline silicon, with only SiC x N y and a 45 ⍀/ᮀ emitter, we obtained 14.9% efficiency.

Effects of Ammonia Addition on Thermal Chemical Vapor Deposition Rates and Microstructures of Carbon Films

“…In the literature, NH 3 was often added in the precursor gas to form various kinds of nitrides. [12][13][14][15][16] Nevertheless, this study reveals that adding NH 3 in CH 4 is not able to produce nitrides in the thermal CVD process. The dissociation energies of NH 3 and CH 4 have been reported as 460 and 431.5 kJ/mole, respectively.…”

Effect of carbon containing SiNx antireflection coating on the screen‐printed contact and low illumination performance of silicon solar cell

“…This information is fed into the System Advisor Model (SAM) from the National Renewable Energy Laboratory to calculate the impact of R sh on annual energy production and levelized cost of electricity (LCOE) in regions of high and low solar insolation. We have shown elsewhere that the starting efficiency of SiN x ‐coated cell is ~0·1–0·2% higher than SiC x N y ‐coated cells due to superior surface passivation. This paper shows that higher R sh of SiC x N y ‐coated cells can nearly make up the difference in efficiency with respect to annual energy production and LCOE.…”

“…SiC x N y ‐coated silicon solar cells generally show slightly lower efficiency (~0·2% absolute) compared with the conventional SiN x ‐coated cells due to inferior surface passivation , but they show slightly lower light‐induced degradation (~0·2% absolute) in commercial grade Czochralski cells resulting in similar stabilized efficiency after light‐induced degradation . In this paper, we have studied the beneficial effect of carbon containing antireflection (AR) coating on screen‐printed metal contact formation and the cell performance under low illumination.…”

Surface Morphology and Optical Reflection of Thermally Evaporated Thin Film Al-Doped Silicon on Plastic Substrates for Solar Cells Applications

“…Thin film Si solar cells are normally produced by chemical vapor deposition (CVD) technique (usually plasma-enhanced type, PECVD) due to its superior resulting film quality (high film conformality due to inherent omnidirectional nature of the deposition) with good electronic properties [5,6]. However, PECVD system suffers from low throughput in the manufacturing lines (with deposition rate of only 20-30 nm/min) [7], safety issue due to the usage of silane gas (SiH 4 ) precursor [8] and high capital, material and operational costs [9].…”