Low-temperature deposition of large-grain polycrystalline Si thin films on polyethylene terephthalate

p-Si thin films with large grains have been fabricated on polyethylene terephthalate substrate by radio frequency plasma enahnced chemical vapor deposition under the assist of negative substrate bias. The micro-structural, optical and electrical properties of the as-deposited thin films are studied by X-ray diffraction, Raman scattering spectroscopy, scanning electron microscope, transmission electron microscopy, optical transmittance spectra and Hall measurement. The test results show that negative bias at moderate level promotes crystallization even at very low substrate temperature (100 degrees C), and the large p-Si grain with the size of similar to 150-300 nm can be obtained at the negative of 100 V. Detailed analysis has been performed for illustrating the effect of negative bias on the growth of p-Si thin film.