Excess low frequency noises in some electronic materials and components

We devised burst noise eliminating equipment and characterized the 1/f and burst noise in some electronic materials, components, electric contacts and bipolar transistors. The burst-eliminated noise spectrum is the 1/f type. The noise intensity is proportional to the square of the current and to the fifth power of the contact resistance. This contact resistance dependence of the noise is analyzed with the constriction resistance of the contact surface material. The measured results are also shown in the amplitude and phase fluctuations in the transistor collector current. They are also of 1/f type and correlate each other. On the other hand, we did not find this correlation in another transistor with burst noise. Hence, the 1/f fluctuation is considered to be due to diffusion or mobility fluctuation and the burst noise is not due to the diffusion process in the solid.