1/f noise of point contacts affected by uniform films

An experimental investigation has been carried out to confirm that contact noise of two crossed semiconductor bars with native oxide films in between can be understood as a volume 1/f noise. Noise and contact resistance have been measured as functions of the force F on the crossed bars. F varies between 6 N and 6×10^-5 N. From a simple model, an equation is derived which relates the 1/f noise intensity C to the contact resistance R. The calculations are in agreement with the experimental C-R plots. Two extreme situations are possible: constriction dominated and film dominated. Which situation actually occurs can be seen in the C-R plot as well as in the R-F plot.