Electrical Resistance Tomography of Conductive Thin Films

TL;DR

This paper demonstrates the application of Electrical Resistance Tomography (ERT) to map the conductance of thin films, accurately imaging spatial distribution and local conductivity with validation against standard measurement techniques.

Contribution

The study introduces a numerical ERT algorithm with total variation regularization for imaging conductive thin films, including patterned samples with null and high conductivity zones.

Findings

ERT accurately images conductance distribution

Reconstructed conductance matches independent measurements

Method effectively images patterned thin films

Abstract

The Electrical Resistance Tomography (ERT) technique is applied to the measurement of sheet conductance maps of both uniform and patterned conductive thin films. Images of the sheet conductance spatial distribution, and local conductivity values are obtained. Test samples are tin oxide films on glass substrates, with electrical contacts on the sample boundary, some samples are deliberately patterned in order to induce null conductivity zones of known geometry while others contain higher conductivity inclusions. Four-terminal resistance measurements among the contacts are performed with a scanning setup. The ERT reconstruction is performed by a numerical algorithm based on the total variation regularization and the L-curve method. ERT correctly images the sheet conductance spatial distribution of the samples. The reconstructed conductance values are in good quantitative agreement with independent measurements performed with the van der Pauw and the four-point probe methods.