PECVD沉积微晶硅薄膜过程中氢原子对透明导电膜的影响

研究了等离子体放电过程中氢原子对单层SnO2和SnO2/ZnO双层透明导电膜的影响.发现当衬底温度超过150℃,H等离子体处理使SnO2薄膜的透光率显著降低.当在SnO2薄膜表面沉积一层ZnO时,既使ZnO膜的厚度为50nm,也可有效地抑制H原子对SnO2的还原效应,并在SnO2/ZnO双层膜上制备了转换效率为3.8%的微晶硅薄膜太阳电池.

Influence of Atomic Hydrogen on Transparent Conducting Oxide During Hydrogenated Microcrystalline Si Preparation by PECVD

The hydrogen plasma degradation of transparent conduction oxides (TCO) is studied for hydrogenated microcrystalline Si(μc-Si:H)prepared by plasma enhanced chemical vapor deposition (PECVD). TCO films such as SnO2 and SnO2/ZnO bi-layer films were exposed to atomic H at various substrate temperatures and for various treatment times. A decrease in the transmittance due to reduction by atomic H was scarcely observed for SnO2/ZnO bi-layer, while a decrease for SnO2 was found to depend strongly on the substrate temperature. The resistivity of SnO2 films decreases significantly when substrate temperature exceeds 150℃ in H-plasma. However,H-plasma treatment has little impact on the resistivity of SnO2/ZnO bi-layer film. The reason for the decrease in the transmittance is the appearance of metallic Sn on the surface, and under this condition no μc-Si: H film is deposited.SnO2/ZnO bi-layer is very effective for the suppression of the reduction of TCO during μc-Si: H deposition. The performance of microcrystalline silicon solar cells fabricated on ZnO/SnO2/glass is also investigated.