PlumX Metrics
Embed PlumX Metrics

Searching a fractal basis for low-frequency 1/f fluctuations -MOSFET structure in case

Japanese Journal of Applied Physics, ISSN: 1347-4065, Vol: 28, Issue: 5R, Page: 929-940
1989
  • 1
    Citations
  • 0
    Usage
  • 1
    Captures
  • 0
    Mentions
  • 0
    Social Media
Metric Options:   Counts1 Year3 Year

Metrics Details

Article Description

We present here a first fractal theory of 1/f noise in MOSFET structures. Inhomogeneous distribution of fixed charges in the gate oxide is assumed to be statistically self-similar, and to produce a fractal interface potential at the oxide-semiconductor interface. The interface is modelled as a special Sierpinski carpet having fractal dimension between 1 and 2. The carpet patches of each stage of fractal’s construction are assigned a uniform interface potential which scales by a constant amount φ at successive stages. This amounts to scaling the interface states time constant by a factor exp ±q|φ|kT at each stage. In framework of this model, we studied the low frequency behaviour of the interface states admittance under weak depletion and strong inversion conditions of the interface. Interface states charge fluctuation is held responsible for generating 1/f noise. In a MOSFET, it manifests through the fluctuations in channel carrier density and surface recombination velocity, and in a MOS capacitor, through direct induction across the oxide capacitance. Frequency exponent is found to be α= 1 ±\frac{kT}{q|\φ|}lna where α-length scale factor and d-fractal dimension. Thus it assumes values on either side of unity depending upon the type of the substrate and sign of Ψ. The theoretical predictions are in good agreement with the experiments. For a soft modulation and even distribution of the interface potential the noise spectrum approaches towards perfect 1/f, and any deviation is distinctly linked with the interface fractality. In essence, we have searched sufficient ground to believe that fractals are at the root of 1/f noise generation. Further, based on this theory we suggest that the noise spectra with α���� should be termed ‘fractal 1/f noise’. © 1989 The Japan Society of Applied Physics.

Provide Feedback

Have ideas for a new metric? Would you like to see something else here?Let us know