Application of liquid phase deposited silicon dioxide to metal-oxide-semiconductor capacitor and amorphous silicon thin-film transistor

Liquid phase deposited silicon dioxide (LPD-SiO2) is applied to crystalline Si metal-oxide-semiconductor (MOS) capacitor as the gate insulator, It is demonstrated that slow states exist at the Si/SiO2 interface which cause hysteresis in the capacitance-voltage (C-V) characteristics. These slow states can be removed effectively by post-metallization-anneal. By means of C-V measurement and infrared absorption spectroscopy, it is concluded that the slow states are originated from the residual water or hydroxyl molecules in LPD-SiO2. The LPD-SiO2 is also applied to fabricate amorphous silicon (a-Si:H) thin film transistor (TFT) based on a new self-aligned process. The performance of this device is comparable to those of thin film transistors employed other kinds of SiO2, i.e., thermal, plasma, vacuum evaporation, etc., as the gate insulator, The bias-stress measurement shows that the threshold voltage shift is dominated by charge trapping in the gate insulator.