Polycrystalline silicon on silicon oxide (poly-Si/SiO_x) passivating contacts enable ultrahigh-efficiency interdigitated back contact silicon solar cells. To prevent shunt between n- and p-type-doped fingers, an insulating region is required between them. We evaluate the use of intrinsic poly-Si for this isolation region. Interdigitated fingers were formed by plasma deposition of doped hydrogenated amorphous silicon through mechanically aligned shadow masks on top of a full-area intrinsic hydrogenated amorphous silicon (a-Si:H) layer. High-temperature annealing then crystallized the a-Si:H to poly-Si and drove in the dopants. Two mechanisms were identified which cause contamination of the intrinsic poly-Si gap during processing. During deposition of doped fingers, we show using secondary ion mass spectrometry and conductivity measurements that the intrinsic gap becomes contaminated by doped a-Si:H tails several nanometers thick to concentrations of ∼10²⁰ cm⁻³. Another source of contamination occurs during high-temperature annealing, where dopants desorb from doped regions and readsorb onto intrinsic a-Si:H. Both pathways reduce the resistivity of the intrinsic gap from ∼10⁵ to ∼10⁻¹Ω·cm. We show that plasma etching of the a-Si:H surface before crystallizing with a capping layer can eliminate the contamination of the intrinsic poly-Si, maintaining a resistivity of ∼10⁵ Ω·cm. This demonstrates masked plasma deposition as a dopant patterning method for Si solar cells.

中文翻译：

---

用本征多晶硅在钝化指状背接触硅太阳能电池中隔离 p 和 n 掺杂指

氧化硅上的多晶硅（poly——硅/硅_X) 钝化触点使超高效率的叉指背接触硅太阳能电池成为可能。为了防止 n 型和 p 型掺杂指之间的分流，它们之间需要一个绝缘区域。我们评估使用内在聚——该隔离区的 Si。通过在全区域本征氢化非晶硅顶部通过机械对准的荫罩，通过掺杂氢化非晶硅的等离子体沉积形成叉指。一种-Si:H) 层。高温退火然后结晶一种-Si:H 到多晶——Si和驱动器中的掺杂剂。确定了两种导致本征多聚体污染的机制——加工过程中的硅间隙。在掺杂指状物的沉积过程中，我们使用二次离子质谱法和电导率测量表明本征间隙被掺杂物污染。一种-Si:H拖尾数纳米厚至~ ^{10 20}  cm ^{-3 的}浓度。另一个污染源发生在高温退火期间，其中掺杂剂从掺杂区解吸并重新吸附到本征上一种-司：H。两种途径都将本征间隙的电阻率从～^{10 5 降低}到～10 ^-1 Ω·cm。我们表明等离子蚀刻一种-Si:H 表面在结晶前用覆盖层可以消除本征多晶硅的污染，保持约^{10 5}  Ω·cm的电阻率。这证明了掩蔽等离子体沉积作为硅太阳能电池的掺杂剂图案化方法。