Resistance drift in Ge2Sb2Te5 phase change memory line cells at low temperatures and its response to photoexcitation

Khan R. S., Dirisaglik F., Gokirmak A., Silva H.

APPLIED PHYSICS LETTERS, cilt.116, 2020 (SCI-Expanded) identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 116
  • Basım Tarihi: 2020
  • Doi Numarası: 10.1063/1.5144606
  • Dergi Adı: APPLIED PHYSICS LETTERS
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, Applied Science & Technology Source, Compendex, Computer & Applied Sciences, INSPEC, DIALNET
  • Eskişehir Osmangazi Üniversitesi Adresli: Evet

Özet

Resistance drift in amorphous Ge2Sb2Te5 is experimentally characterized in melt-quenched line cells in the range of 300K to 125K and is observed to follow the previously reported power-law behavior with drift coefficients in the range of 0.07 to 0.11 in the dark, linearly decreasing with 1/kT. While these drift coefficients measured in the dark are similar to commonly observed drift coefficients (similar to 0.1) at and above room temperature, measurements under light show a significantly lower drift coefficient (0.05 under illumination vs 0.09 in the dark at 150K). Periodic on/off switching of light shows a sudden decrease/increase in resistance, attributed to photo-excited carriers, followed by a very slow response (similar to 30min at 150K) attributed to contribution of electron traps and slow trap-to-trap charge exchanges. A device-level electronic model is used to relate these experimental findings to gradual charging of electron traps in amorphous Ge2Sb2Te5, which gives rise to growth of a potential barrier for holes in time and, hence, resistance drift. Published under license by AIP Publishing.