Effect of argon on the structure of hydrogenated nanocrystalline silicon deposited from tetrachlorosilane/hydrogen/argon plasma

Hydrogenated nanocrystalline silicon films (nc-Si:H) have been deposited by the decomposition of tetrachlorosilane (SiCl4) diluted with hydrogen (H2) and argon (Ar) by a plasma-enhanced chemical vapor deposition (PECVD) method. Basing on the structural characterization of nc-Si:H, we have found that Ar affects the growth of films deposited at two substrate temperatures (Ts?=?250 and 120 degrees C) in different ways. At Ts?=?250 degrees C, the Ar gas deteriorates the crystallinity of nc-Si:H, whereas, at Ts?=?120 degrees C, the crystallization of nc-Si:H films is promoted with increasing argon flow rate (Hf) from 10 to 30?sccm; however, the extremely high Ar dilution adversely affects the ordered structure of films. Meanwhile, the hydrogen concentration in the films is also controlled by Hf. Finally, the effects of Ar in the SiCl4/H2/Ar system have been discussed in related to the equilibrium of atomic hydrogen and ionized argon.