1/f noise in bismuth ruthenate based thick-film resistors

We report measurements of 1/f noise in bismuth ruthenate (Bi/sub 2/Ru/sub 2/O/sub 7/) thick-film resistors in the frequency range of 1 Hz to 40 kHz including the dependence of the noise on the bias current, resistance in the range 1 k/spl Omega/ to 400 k/spl Omega/ and laser trimming effects. The noise spectra show that the magnitude of the noise parameterized by the relative noise index parameter C has the approximate dependence given by C=3/spl times/10/sup -15/ (R/sub s/n/sub s/)/sup 0.6/, where n/sub s/ is the aspect ratio and R/sub s/ is the sheet resistance. Technologically this is an important result since it allows the prediction of the approximate level of noise for any resistor made from the BIROX series compounds from the ink resistivity and the dimensions of the resistor. The link between the noise magnitude and noise models is examined.