Fast deposition of microcrystalline Si films from SiH 2Cl 2 using a high-density microwave plasma source for Si thin-film solar cells

Abstract

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 SiH 4–H 2 and SiH 2Cl 2–H 2 mixtures. The film crystallization was promoted efficiently when film was fabricated using SiH 4 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 SiH 2Cl 2, 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.