Deposition of device grade poly-Si films on glass substrate directly at 450 °C and fabrication of bottom-gate poly-Si TFTs

We have observed the progressive stages of nucleation and growth of the poly-Si films with the source gasses of Si2H6 and F2 on glass substrates directly at 450 °C and found that nuclei density and size are controllable effectively via governing process pressures. We introduced a nuclei governed layer of approximately less than 2 nm and it brought about 33% increases in grain diameter. Finally, we fabricated n- and p-channel bottom-gate TFTs whose field effect mobility was higher than 50 cm2/V s. However, the devices with the nuclei governed layers faced degradation due to the propagation of fluorine into gate oxide. Therefore, it needs further studies.