Long range diffusion noise in platinum micro-wires with metallic adhesion layers

TL;DR

This study investigates voltage fluctuations in platinum micro-wires with and without adhesion layers, revealing that adhesion layers induce a different noise spectrum due to hydrogen diffusion, which impacts the wires' electrical stability.

Contribution

It demonstrates how adhesion layers alter the noise spectrum in platinum wires, linking the change to hydrogen diffusion dynamics, a novel insight into micro-wire noise behavior.

Findings

Wires without adhesion layers exhibit a $1/f$ noise spectrum.

Wires with adhesion layers show a $1/f^{3/2}$ noise spectrum.

Hydrogen diffusion from adhesion layers influences the noise characteristics.

Abstract

Voltage fluctuations of Platinum wires hosted by silicon nitride beams were investigated. We considered four variants of the wires: three with an adhesion layer and one with no adhesion layer. We found that the presence of an adhesion layer changes the nature of the power spectrum which is $1/f$ for wires with no adhesion layers and $1/f^{3/2}$ for wires with an adhesion layer. We attribute the value of the exponent $\alpha=3/2$ to the long range diffusion of hydrogen originating from adhesion layers that undergo a migration through the Pt wires.