We investigated the deposition condition of the plasma processing for the formation of as-grown poly-Si thin film on the SiO2 substrate with low temperature (300 degrees C) processing. We intended to compensate the thermal energy loss due to the low temperature processing with the low kinetic energy, ion bombardment assist. We adopted both plasma enhanced chemical vapor deposition (PECVD) (SiH4/Ar/H-2) and sputtering (Si-target/Ar/H-2) processes. Plasma parameters were measured by the advanced Langmuir probe method tuned for 182.5 MHz rf plasma. Crystallinity of the him was estimated mainly by x-ray diffraction. Crystallization occurred by in situ hydrogenation during the deposition. In our experiment, ion bombardment energy was approximately 23 eV. We define the normalized ion (ni) flux number and investigated the correlation between the ni and the him crystallinity. The result is as follows, the crystal size enlarges with the increasing ni up to similar to 20 but it diminishes as the ni increases over similar to 20. Under the same plasma condition, the PECVD processed Si films have better crystallinity than the sputtering processed ones. The film thickness and crystal size are 1000 and 219 Angstrom, respectively, at the optimum value of the ni in the PECVD process. Atomic hydrogen is thought to be very effective for the crystallization of the film and, as for the ion assist effect, there exists an optimum value of ni for a certain ion bombardment energy.