Low-Frequency Noise Properties in P-Type SnO Thin-Film Transistors

We examine the low-frequency noise (LFN) properties of p-type tin monoxide (SnO) thin-film transistors (TFTs). The noise power spectral densities of the drain current are proportional to 1/f(alpha) with alpha similar to 1 in the frequency range 10 Hz to 1 kHz. The LFN from the p-type SnO TFT is successfully interpreted by the correlated carrier number-mobility fluctuation model, but neither the mobility fluctuation model nor the carrier number fluctuation model can explain the observed LFN behaviors. The density of near-interface insulator traps that can exchange charge carriers with the underlying SnO channel layer is found to be 5.2x10(21) eV(-1) cm(-3), which is approximately one or two orders of magnitude higher than that of the n-type amorphous indium-gallium-zinc oxide TFTs. The high density of the near-interface insulator trap from the SnO TFT is considered to be a result of the high degree of disorder of the SnO channel layer.