Hydrogen motion and 1/f noise in hydrogen amorphous silicon thin films

We report studies of flicker noise in n-type hydrogenated amorphous silicon (a-Si:H) resistive devices from room temperature to about 420 K. The device is first annealed at 450 K and then cooled to room temperature either at a rate of 0.5 Ws or 0.02 K/s. The voltage noise power spectra, S-v(f), and the conductance of the device are characterized from room temperature to 420 K. The Arrhenius plots of both S-v(f) and the conductance exhibit typical thermal equilibration process commonly observed in a-Si:H materials. Characterizations of the bias dependencies of the noise show that S-v(f) deviate from I-2 dependence indicating that the noise arises from a non;linear mechanism, Also, S-v(f) scales as to R-p where p is dependent on the temperature and the cooling process. Our experimental data provides strong evidence that the flicker noise originates from hydrogen motion within the material, The process appears to cause fluctuations in the device conductance by modulating the percolation path of the carriers.