Low-frequency noise measurements have been carried out at room temperature in polycrystalline semiconducting iron disilicide (β-FeSi2) thin film with the current I as a parameter. The power spectral density of the current fluctuations exhibits a 1/f behavior at low frequencies (f<100 Hz) and is proportional to Iβ (β<2). The temperature dependence of the conductivity shows that, at room temperature, the measured noise is related to a thermally activated transport mechanism, which satisfies the Meyer–Neldel rule. A noise theory has been developed on the basis of trapping-detrapping of holes of the valence band and the gap states taking into account mobility inhomogeneity across the thickness of the film. Using the experimental data of Hall, conductivity, and noise measurements, the noise model provides an assessment of the distribution of traps within the energy gap of the β-FeSi2 material.

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The influence on magnetic field on l/fnoise in a planar GaAs resistor grown by molecularbeam epitaxy and without surface effects was investigated experimentally. The experimental results can be explained by the number fluctuation model but not by the mobility fluctuation modeL Previously, experimental results indicating number fluctuation type of l/fnoise were mostly attributed to the surface effects associated with the particular structures used for the experiments. In our device the surface effects were diminished so that the fluctuations of the bulk current could be considered to produce the 1/fnoise.

Effects of the gate dielectric nitridation on the flicker (1/f) noise characteristics of submicron metal oxide semiconductor field effect transistors (MOSFETs) are reported. Low-frequency (1/f) noise measurements on nitrided and non-nitrided gate oxide MOSFETs of the same geometry have been carried out, showing different noise behavior with respect to the flicker noise amplitude and bias dependence. It is found that gate oxide nitridation not only increases the flicker noise amplitude, but also enhances the correlated mobility noise mechanism. The two orders of magnitude higher noise measured in nitrided structures is consistent with the approximately two orders of magnitude increase of the nitrided gate conductance reported in the literature.

By replacing the change in velocity Av by the low-frequency Fourier transform F,{0)of the electron acceleration a{t), Handel's equations for the Hooge parameter a~are put in equivalent forms that are not only applicable to collision I/f noise in semiconductors but also to acceleration I /f noise in long semiconductor resistors. To prove these expressions semiclassically, one evaluates first the bremsstrahlung energy dE of a single radiation pulse in a frequency interval df, and then defines dn =dE/hf as the number of photons of a single radiation pulse in a frequency interval df and finally dr =dn /~, =dE/hf r, as the rate of photon emission in a single pulse in a frequency interval df It is then. found that the expression for dr already contains the Hooge parameter aIt. It thus seems that the Hooge parameter depends only on the bremsstrahlung emission process but not on the details of the electron-photon interaction. This may explain why handel's expressions for az so often agree with experiment. One must now bear in mind that the elementary current event is described by a current pulse i{t) of duration~, having a Fourier transform F;{0). If one next defines S""(f)=dr/df, then the current noise spectrum is obtained by multiplying S""(f) first by 2F;{0),to obtain the effect of a single elementary event per second, and then multiply by A, , the number of elementary events per second. This leads immediately to the Hooge equation and to the Hooge parameter cx~.