Excess low frequency noises in some electronic materials and components.

We arranged a burst noise eliminating equipment and characterized the l/f and burst noises in some electronic materials, components, the 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 on the noise is analyzed with the constriction resistance of the surface material of the contact. The measured results are also shown on the amplitude and phase fluctuations in collector current of the transistor. They are also of 1/f type and correlate each other. On the other hand, we can not find the correlation in another transistor with burst noise. Hence, the l/f fluctuation is considered to be due to diffusion or mobility fluctuation and the burst noise is not from the diffusion process in the solid.