1/f noise measurements for characterizing multispot low-Ohmic contacts

Abstract

The patchiness of contacts can be determined from measurements of 1/f noise and contact resistance on a number of contacts of different diameters made by the same method. If a contact consists of k conducting spots with average radius a, k and a can be determined if the distance between the spot centers is at least 2.5 times the spot diameter. Using the developed multispot contact model, the results of the 1/f noise analysis are in good agreement with multispot parameters obtained from microscopic investigations.

Low-frequency noise sources in as-prepared and aged GaN-based light-emitting diodes

“…For example, it has been shown that alloying of AuSi contact film on GaAs at temperatures 450°C and higher causes the formation of globules, thus creating a multispot contact area. 36 It is possible that a similar effect could occur in a Pt/ GaN contact system. In the S50 device we assume that a local current density of at least 2 ϫ 10 6 A/cm 2 must exist at the rim of the semitransparent window and the area around the bonded wire.…”

“…A very noisy contribution is assumed to be in series with an almost noise-free contribution similar to multispot contact problems. 9,[34][35][36] The onset of contact degradation leads to current crowding and enhanced noise. The noise of a large part of the series resistance can remain unaffected by the degradation.…”

1/f noise as a diagnostic tool to investigate the quality of isotropic conductive adhesive bonds

“…The patchiness parameters and are the number of spots and the spot radius, respectively, while is the distance between the spot centers. The resistance and noise were calculated for a general multispot contact [7]. The electrical contact area is smaller than the apparent conducting area , which explains the discrepancy between experimentally observed resistance and calculated resistance from .…”

“…The analysis of the results is based on a model for multispot contacts in [7]. In a special case of multispot contacts with -conducting spots, with diameter , far apart from each other, and can be calculated [7], [8].…”

Criteria of low-noise thick-film resistors

“…Patchy contacts at a metal-semiconductor interface have been studied quantitatively by using contact resistance and noise measurements. 6 1/f noise measurements were recommended as a diagnostic tool for research on thick-films, 1,7 for thinfilm metalization patterns 8 and for quantitative characterization of contacts in general. 6'9 Considering the distribution of metal oxide grains in the poor conducting matrix, most thick-film resistors are homogeneous.…”