The influence of Bi doping on the charge carrier transport mechanism in GST225 thin films was investigated. The three regions with different current-voltage dependencies were established. The energy diagrams for Bi doped GST225 thin films for different regions were analyzed. Analysis of experimental data showed that space charge limited current is the most possible explanation for the nonlinear I-V dependence in the middle electrical field strength (10³ < E < 10⁴ V/cm). Position of the trap levels (Et) controlling transport mechanism, and density of traps (Nt) were estimated with using of Rose and Lampert theories. It was established that Bi doping can significantly change I-V characteristic, resistivity, mobility gap, Urbach energy, density distribution of localized states, and activation energy of conductivity. The most pronounced modification of current-voltage characteristic and parameters of the thin films was established for GST225 + 0,5 wt. % Bi. Thus, doping of Ge₂Sb₂Te₅ by Bi expands the range of material properties, which is important for the optimization of PCM technology.

Date Published: 18 December 2014
PDF: 9 pages
Proc. SPIE 9440, International Conference on Micro- and Nano-Electronics 2014, 944006 (18 December 2014); doi: 10.1117/12.2180999

Published in SPIE Proceedings Vol. 9440:
International Conference on Micro- and Nano-Electronics 2014
Alexander A. Orlikovsky, Editor(s)