1/f noise in p-type amorphous silicon

We have measured conductance fluctuations in four samples of p-type hydroge nated amorphous silicon, two doped at 10(-4) and the other two at 5 x 10(-2 ), at temperatures between 22 and 200 degrees C, The noise power density va ries for the most part as 1/f(alpha) in the frequency range 2 Hz to 1 Wt, a lthough deviations from a strict power law are observed. In all samples, th e magnitude of the noise trends higher with temperature typically increasin g by a factor of 5 over the temperature range. alpha also increases with te mperature from near unity to over 1.4. The magnitude of the noise decreases as the Fermi level moves toward the valence band with increased doping. Th e dependence on doping and temperature is inconsistent with generation-reco mbination noise. Above 180 degrees C for the 10(-4) doped samples, the nois e fails to scale as the square of the bias current at low frequencies. (C) 2000 American Vacuum Society. [S0734-2101(00)03602-2].