Variable resistor made by repeated steps of epitaxial deposition and lithographic structuring of oxide layers by using wet chemical etchants

TL;DR

This paper reports the fabrication of variable resistors using epitaxial oxide layers with lithographic patterning and wet chemical etching, demonstrating controlled conductance changes similar to traditional devices.

Contribution

It introduces a novel method combining epitaxial growth, lithography, and wet chemical etching to create variable resistors from complex oxide materials.

Findings

Good epitaxy achieved after wet chemical etching and polishing.

Devices exhibit conductance modulation similar to shadow mask-defined resistors.

Optimized etchants enable precise patterning of oxide layers.

Abstract

Variable resistors were constructed from epitaxial SrRuO3 (SRO), La0.67Sr0.33MnO3 (LSMO) and SrTiO3 layers with perovskite crystal structure. Each layer was patterned separately by lithographic methods. Optimized wet chemical etchants and several polishing steps in organic solvents allowed good epitaxy of subsequent layers, comparable to epitaxy on pristine substrates. Periodate as the oxidizing agent for SRO and iodide with ascorbic acid as the reducing agents for LSMO were used to attack these chemically resistant oxides. The final devices changed their conductance in a similar manner to previously described variable resistors that were defined with shadow masks.