Influence of the deposition temperature on the performance of microcrystalline silicon thin film transistors

Bottom gate microcrystalline silicon thin film transistors (μc-Si:H TFT) have been fabricated at three different deposition temperatures (150, 200 and 250 °C) for the μc-Si layer. We found that the linear field effect mobility increases from 0.1 to 0.44 cm²/V s by decreasing the temperature from 250 °C to 150 °C, and that the leakage current of TFTs with μc-Si deposited at 150 °C is lower than that of μc-Si:H deposited at 250 °C. Moreover, there is no influence of the deposition temperature on the stability of μc-Si:H TFTs. The improvement of the electrical characteristics at lower deposition temperatures is discussed in terms of a lower concentration of donor active oxygen atoms at lower temperature.