Measuring Electrical Resistivity at the Nanoscale in Phase-Change Materials

• Published in: Nano letters Vol. 24; no. 19; pp. 5913 - 5919
• Main Authors: Zhang, Leifeng, Lorut, Frédéric, Gruel, Kilian, Hÿtch, Martin J., Gatel, Christophe
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 15-05-2024
• Subjects: Physics; finite element modeling; operando experiments; electron holography; electrical resistivity; phase-change materials; in situ TEM
• ISSN: 1530-6984; 1530-6992
• DOI: 10.1021/acs.nanolett.4c01462

Electrical resistivity is the key parameter in the active regions of many current nanoscale devices, from memristors to resistive random-access memory and phase-change memories. The local resistivity of the materials is engineered on the nanoscale to fit the performance requirements. Phase-change memories, for example, rely on materials whose electrical resistance increases dramatically with a change from a crystalline to an amorphous phase. Electrical characterization methods have been developed to measure the response of individual devices, but they cannot map the local resistance across the active area. Here, we propose a method based on operando electron holography to determine the local resistance within working devices. Upon switching the device, we show that electrical resistance is inhomogeneous on the scale of only a few nanometers.