The Effect of Processing Parameters on Resistivity of Boron-doped Hydrogenated Nanocrystalline Silicon Thin Films

The boron-doped hydrogenated nanocrystalline silicon (nc-Si:H) thin films were deposited by plasma enhanced chemical vapor deposition (PECVD). The microstructures of boron-doped nc-Si:H films were characterized and analyzed by Raman spectrum and atomic force microscopy(AFM). The thickness of the films was measured by high-resolution profilometer. The resistivity of the films was measured by four-point probe. The effect of boron-doped concentration, film thickness, substrate temperature, as well as the annealing temperature on resistivity of boron-doped nc-Si:H thin films was studied. The results show that the resistivity of nc-Si:H thin films decreases sharply and stabilizes eventually with the increasing boron-doped concentration when the boron-doped concentration is more than 0.5%, and when the thickness of boron-doped nc-Si:H thin films is less than 100nm, the resistivity of boron-doped nc-Si:H thin films is much higher than that of the films whose thickness is more than 200nm, but when the thickness of the film is more than 200nm, the resistivity of films falls into a sharp decline and then becomes stable with the increasing thickness. Resistivity of boron-doped nc-Si:H thin films drops after annealing, but it rises with the increasing annealing temperature.