Poly-crystalline silicon thin films prepared by plasma-assisted hot-wire chemical vapor deposition

A combination of hot-wire chemical vapor deposition (HWCVD) and RF plasma, referred to as plasma-assisted HWCVD (P-HWCVD) was used to prepare poly-crystalline silicon (poly-Si) thin films. The effects of the plasma on the film properties were studied by varying the RF power (P_w) from 0 to 40 W. The results indicate that, compared with that of HWCVD samples, the film crystalline fraction (X_c) is enhanced at low P_w assistance, whereas it decreases at higher P_w. The uniformity of the film thickness is considerably improved by introducing plasma. It is also found that the porosity of the film, indirectly detected from infrared spectra, is much reduced. Auger analysis of the tantalum filament used in the P-HWCVD process shows much lower silicon contamination than that in HWCVD.