Abstract
KGaA, Weinheim. We study the effects of nitrogen (N)-doping on the electrical memory reliability of GeSbTe phase-change materials based on GeTe prototype models. We find that the loss of secondary bonding (e.g., resonant interlayer bonding) determines the feasibility of various types of N-doping that can be easily adopted by the GeSbTe system. We give a more generalized explanation beyond compliance with the formation of local Ge3N4 motifs. The nitrogen-induced change in local order produces crystalline GeTe with shallow states near the valence band edge. These states are localized on the nearest-neighbor Ge sites, thus reducing the conductivity in the crystalline phase. This trend carries over to c-GeTe with Ge vacancy. The N-doped amorphous GeTe models exhibit enhanced degrees of band tail overlap, which pins the Fermi energy in the mid-gap and thus gives rise to even higher resistivities in the amorphous phases.
Original language | English |
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Pages (from-to) | 431-441 |
Number of pages | 11 |
Journal | Physica Status Solidi (B) Basic Research |
Volume | 252 |
Issue number | 2 |
DOIs | |
Publication status | Published - 1 Jan 2015 |
Externally published | Yes |
Keywords
- Band overlapping
- Loss of secondary bonding
- N-doping
- Phase change memory materials
- Shallow states
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics