Nature of low-frequency noise in homogeneous semiconductors

Abstract

This report deals with a 1/f noise in homogeneous classical semiconductor samples on the base of silicon. We perform detail calculations of resistance fluctuations of the silicon sample due to both a) the charge carrier number changes due to their capture–emission processes, and b) due to screening effect of those negative charged centers, and show that proportionality of noise level to square mobility appears as a presentation parameter, but not due to mobility fluctuations. The obtained calculation results explain well the observed experimental results of 1/f noise in Si, Ge, GaAs and exclude the mobility fluctuations as the nature of 1/f noise in these materials and their devices. It is also shown how from the experimental 1/f noise results to find the effective number of defects responsible for this noise in the measured frequency range.

Low-frequency noise characteristics of high-power white LED during long-term aging experiment

“…2(a)). In the majority of semiconductor devices 1/f α -type fluctuations originate from a superposition of many charge carrier generation-recombination (g-r) processes in the capture centres with widely distributed relaxation times [15]. These centres are formed during device fabrication and also during ageing due to the device degradation.…”

The charge carrier capture–emission process – the main source of the low-frequency noise in homogeneous semiconductors

“…[35], the minimum number of relaxators (defects) has been estimated with relaxation times distributed in a wide time range needed for the generation of noise with the 1/f spectrum. It has been shown that this requirement is fulfilled when the relaxation times are arbitrarily distributed one-by-one in every two-octave range.…”

“…1, a (11) in Ref. [35] must be changed to the factor 0.16. The curve g(τ) for K = 1 has only small waves or bumps compared with g 0 (f).…”

“…In the case when K relaxators are non-uniformly arbitrarily distributed in the logτ scale, one will obtain the low-frequency noise spectra with bumps or waves about 1/f law or 1/f γ type spectra. On the ground of this analysis, instead of the characterization of the 1/f noise level in homogeneous materials by the Hooge parameter α [3,13], Palenskis [35] proposed a general expression for the 1/f noise caused by the charge carrier capture-emission process accounting for additional resistance fluctuation because of the Debye screening effect of negatively charged centers due to the electron capture ,…”

“…K is the average number of relaxators in the sample with arbitrarily distributed relaxation times in every double octave, and δ is the factor accounting for additional resistance fluctuation due to the Debye screening effect; for Si it can be approximated as δ ≈ (1.3 + 6.5 · 10 17 /n) 0.65 (here n in cm -3 ) when the defects are localized in the volume of the sample [35]. In the case when defects are localized on the surface of the sample, number 6.5 in the expression for δ must be decreased by 2 times.…”