Influence of Cu Doping in Si–Te-Based Chalcogenide Glasses and Thin Films: Electrical Switching, Morphological and Raman Studies

To understand the electrical switching behavior of Si
₁₅
Te
_85-x
Cu
_x
(1≤ x ≤10) series, I-V characterization has been performed on bulk as well as amorphous thin films of the as-prepared samples. Both the bulk glasses and amorphous thin films are found to manifest memory-type switching behavior. The threshold voltages of thin-film devices are found to be much lower than the bulk counterparts and hence could find application for phase change memory (PCM). The composition analyses of both have divulged the existence of intermediate phase (IP) in the composition range of 2 ≤ x ≤ 6. To examine the probability of the given glass for PCM application, Set-Reset studies have been performed on the glasses with a triangular pulse of 6 mA for set operation and rectangular pulse of 12 mA for the reset operation. The study has revealed a continuous repetition of few Set-Reset cycle by the Si-Te-Cu series. Raman studies carried out on the bulk glasses report the occurrence of blue shift over the composition in a regular manner. Further, SEM studies have been carried out on Si-Te-Cu samples to understand the morphological changes that would have occurred during switching. Additionally, thickness dependence of threshold voltage of representative Si
₁₅
Te
₈₀
Cu
₅
and Si
₁₅
Te
₇₆
Cu
₉
glasses has been carried out to reveal the relationship between threshold voltage and thickness.