Low-frequency noise in a thin active layer α-Si:H thin-film transistors

Low-frequency noise of hydrogenated-amorphous-silicon (alpha-Si:H) thin-film transistors (TFTs) with a thin active layer and an inverted staggered device structure operating in the conducting mode has been investigated. Pure 1/f-noise spectra were observed. The results show that the physical location of the noise in alpha-Si: H TFTs is different from that in crystalline metal-oxide-semiconductor field-effect transistors. The noise contributions from the channel and interface have been determined for the device operating in different modes. The 1/f noise of alpha-Si:H TFTs stems from the channel when the device is operated in the linear region at high gate voltages. However, the 1/f noise of alpha-Si:H TFTs generated at the interface becomes significant when the device is operated in the saturation region. The interface noise can be explained by the number fluctuation model (Delta N model). The channel noise can be explained by either the Delta N model or the mobility fluctuation model (Delta mu model). (C) 1999 American Institute of Physics. [S0021-8979(99)04811-2].