Fast deposition of microcrystalline Si films from SiH2Cl2 using a high-density microwave plasma source for Si thin-film solar cells

Fast deposition rate of 27 Å/s for microcrystalline (μc-) Si films was investigated using a high-density and low-temperature microwave plasma source with a spoke antenna of SiH4–H2 and SiH2Cl2–H2 mixtures. The film crystallization was promoted efficiently when film was fabricated using SiH4 with an aid of large amount of hydrogen atom, while the volume fraction of void in the film was relatively the larger of 10–20%. On the other hand, the volume fraction of amorphous silicon phase in the μc-Si films were 20–30% with no significant void fractions in films fabricated from SiH2Cl2, although the volume fraction of the crystalline silicon phase was 75–85%. The role of chlorine in the growth of μc-Si films is discussed in terms of the chemistry of the H and Cl terminated growing surface. The preliminary result of p–i–n Si thin-film solar cell is demonstrated using μc-Si:H:Cl films as an intrinsic layer.