1/f NOISE DUE TO ATOMIC DIFFUSION OF IMPURITY CENTERS IN SEMICONDUCTORS

Abstract

Atomic diffusion of impurity centers is investigated as a possible origin of 1/f noise in semiconductors. Following the trace of an individual impurity center, the noise produced at a certain site is calculated; due to diffusion of centers this is an intermittent process. Besides generation-recombination (= g-r) noise, an excess noise is obtained which is attributed to diffusion of impurity centers. This excess noise exhibits 1/f noise and g-r burst noise. 1/f noise is attributed to the return time of a center to the origin; g-r burst noise is the noise produced by centers residing at a certain site. For a n-type strongly extrinsic semiconductor, the Hooge coefficient α of the present model is derived and impact of compensating acceptors or additional doping by shallow centers is investigated. Increasing the concentration of additional shallow centers α is decreased; an increase of concentration of compensating acceptors results in an increase of α. The temperature dependence of the Hooge coefficient α(T) is calculated and is compared with empirical findings.