Comment on 'Comparison of excess 1/f noise spectra in trimmed and untrimmed thick film resistors'

The paper by Peled et al. (2000, International Journal of Electronics, 87, 1-9) reports a quantitative comparison between the low frequency excess 1/f noise obtained on trimmed and untrimmed bismuth ruthenate thick film resis tors (TFRs). The empirical relation of Hooge was used to quantify and compa re the 1/f noise level. Peled et al. concluded that the Hooge parameter alp ha (H) increases for trimmed TFRs. In this comment it will be shown that mi susing the Hooge relation for nonhomogeneous materials can lead to misleadi ng high apparent alpha values describing not the 1/f properties of the mate rial but the current crowding in the material.