Passivating contacts based on polycrystalline silicon (poly-Si) on an interfacial oxide are limited by parasitic absorption, which may be reduced by incorporation of foreign elements in the poly-Si layer. In this study, the influence of carbon incorporation in the concentration range of 6.9–21.5 at% on boron-doped polycrystalline silicon carbide (poly-SiCx) layer properties is investigated and interpreted in the context of an application as full-area passivating contact on the front side of a solar cell. For constant annealing parameters, higher carbon concentrations reduce the crystallinity of the layers. A high crystallinity in turn is confirmed to be a key parameter for the application in a solar cell as it ensures both low resistivity as well as low parasitic absorption. Low recombination current densities in the range of 7.2–12.2 fA/cm2 are determined for all layers on interfacial oxides on planar surfaces, whereas the differences are rather related to variations in the boron concentration than to the carbon concentration or the deposition parameters. A reduction of the (p) poly-SiCx layer thickness down to 10 nm would yield a parasitic absorption current density of 1.13 ± 0.13 mA/cm2. Using this value and the lowest measured recombination current density, a simple model predicts a theoretical solar cell efficiency limit of 26.7 ± 0.2%.

中文翻译：

---

碳浓度对 (p) Poly-SiC$_{\text x}$ 层特性的影响，重点关注正面 Poly-SiC$_{\text x}$/SiO$_{\text x} 中的寄生吸收$ 太阳能电池的钝化触点

基于界面氧化物上的多晶硅 (poly-Si) 的钝化触点受到寄生吸收的限制，寄生吸收可以通过在多晶硅层中加入外来元素来减少。在这项研究中，在 6.9-21.5 at% 浓度范围内的碳掺入对掺硼多晶碳化硅 (poly-SiCx) 层特性的影响进行了研究，并在应用的背景下解释为全面积钝化接触太阳能电池的正面。对于恒定的退火参数，较高的碳浓度会降低层的结晶度。反过来，高结晶度被证实是太阳能电池应用的关键参数，因为它确保了低电阻率和低寄生吸收。7.2-12 范围内的低复合电流密度。2 fA/cm2 是针对平面表面上的界面氧化物上的所有层确定的，而差异与硼浓度的变化有关，而不是与碳浓度或沉积参数有关。将 (p) poly-SiCx 层厚度降低至 10 nm 将产生 1.13 ± 0.13 mA/cm2 的寄生吸收电流密度。使用该值和测得的最低复合电流密度，一个简单的模型预测理论太阳能电池效率极限为 26.7 ± 0.2%。13 毫安/平方厘米。使用该值和测得的最低复合电流密度，一个简单的模型预测理论太阳能电池效率极限为 26.7 ± 0.2%。13 毫安/平方厘米。使用该值和测得的最低复合电流密度，一个简单的模型预测理论太阳能电池效率极限为 26.7 ± 0.2%。