Nucleation Control by Intermittent Supply of Dichlorosilane towards the Fabrication of Polycrystalline Silicon Thin Films with Large Grain Size

To obtain polycrystalline Si (poly-Si) thin films with large grain size, we propose a nucleation control method by intermittent supply of Si source gas in atmospheric pressure chemical vapor deposition. By intermittent supply of dichlorosilane as Si source gas, the nucleus density was controlled to between 105 and 107 cm-2. The maximum grain size of 22 μm with a film thickness of 15 μm was obtained. By optimizing the conditions of intermittent ratio and time, a relatively high preferential orientation of (220) over 65% was achieved. In addition, the poly-Si thin film with continuous columnar structure was obtained.