Hot-carrier trap-limited transport in switching chalcogenides

TL;DR

This paper develops a comprehensive physical model for charge transport in amorphous chalcogenide materials, explaining their switching behavior and providing insights into threshold conditions relevant for memory device applications.

Contribution

The paper extends existing trap-limited conduction models by incorporating position-dependent carrier concentration and field, offering a more accurate description of switching in chalcogenides.

Findings

Model reproduces experimental electrical characteristics

Provides physical interpretation of switching mechanism

Estimates threshold conditions based on material parameters

Abstract

Chalcogenide materials have received great attention in the last decade owing to their application in new memory systems. Recently, phase-change memories have, in fact, reached the early stages of production. In spite of the industrial exploitation of such materials, the physical processes governing the switching mechanism are still debated. In this paper we work out a complete and consistent model for transport in amorphous chalcogenide materials based on trap-limited conduction accompanied by carrier heating. A previous model is here extended to include position-dependent carrier concentration and field, consistently linked by the Poisson equation. The results of the new model reproduce the experimental electrical characteristics and their dependences on the device length and temperature. Furthermore, the model provides a sound physical interpretation of the switching phenomenon and is able to give an estimate of the threshold condition in terms of the material parameters, a piece of information of great technological interest.