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Temperature and frequency dependence of flicker noise in degenerately doped Si single crystals

Kar, Swastik and Raychaudhuri, AK (2001) Temperature and frequency dependence of flicker noise in degenerately doped Si single crystals. In: Journal of Physics D: Applied Physics, 34 (21). pp. 3197-3202.

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We report measurements of low-frequency $(10^{-2} Hz < f < 20 Hz)$ conductance fluctuations (flicker noise) over a temperature range 150 K < T < 450 K in single crystalline Si across the insulator–metal transition by doping with phosphorus and boron $(\sim10^{19} cm^{-3})$. In this range of doping the noise (as quantified by the Hooge’s parameter) is much larger than that seen in lightly doped Si. The f and T dependence shows a 1/f component whose strength increases exponentially with T (with activation energy ≈0.1–0.2 eV) although the resistivity is almost flat in this temperature range. For a sample on the metallic side of the transition the behaviour of the conductance fluctuation is very similar to that of disordered metals with the spectral power, $S_V (f )\propto 1/f^\alpha with \alpha \approx 1–1.2$. This is proposed to arise from the movement of defect complex involving P and interstitials/vacancies following a broad activated kinetics. Interestingly in a heavily doped sample, lying on the insulating side (but close to the insulator–metal transition) the spectral power contains discrete Lorentzians in addition to the 1/f term. The corner frequencies have an activated behaviour with activation energy ≈0.45–1 eV. This behaviour, most likely, originates from recombination-generation type mechanisms.

Item Type: Journal Article
Publication: Journal of Physics D: Applied Physics
Publisher: Institute of Physics
Additional Information: Copyright of this article belongs to Institute of Physics.
Department/Centre: Division of Physical & Mathematical Sciences > Physics
Date Deposited: 17 Jun 2006
Last Modified: 19 Sep 2010 04:29
URI: http://eprints.iisc.ac.in/id/eprint/7674

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