Temperature-Dependent Electronic Transport in Non-Bulk-Resistance-Variation Nitrogen-Doped Cr2Ge2Te6Phase-Change Material

The electronic transport mechanism of the nitrogen-doped Cr2Ge2Te6(NCrGT) phase-change material (PCM) is studied, showing almost zero resistivity variation upon phase transition. A similar low-temperature variable-range hopping (VRH) behavior in both the amorphous and crystalline phases of the NCrGT PCM is observed by measuring the temperature-dependent resistivity. At high temperatures above 300 K, the conduction mechanism in the amorphous NCrGT is thermally activated band conduction, while the carrier transport in the crystalline NCrGT is still driven by VRH. Moreover, Hall property measurements reveal a thermally activated carrier in the amorphous NCrGT and mobility-driven hopping conduction in the crystalline NCrGT at a high temperature range from 300 to 400 K. The conduction mechanism difference between the amorphous and crystalline NCrGT/tungsten (W) contacts is further investigated by measuring the temperature-dependentI-Vcharacteristics. The conduction in the amorphous NCrGT/W contact is dominated by thermionic-field emission, while the transport mechanism through the crystalline NCrGT/W interface is controlled by the defect-assisted tunneling current. Such noticeable conduction mechanism variation results in a large contact resistance contrast in a memory cell.

Automated summary

The electronic transport mechanism of nitrogen-doped Cr2Ge2Te6 phase-change material shows almost zero resistivity variation upon phase transition. Different transport mechanisms are observed at different temperature ranges, leading to significant contact resistance contrast in memory cells.