Publications

Role of Oxygen on Chemical Segregation in Uncapped Ge₂Sb₂Te₅ Thin Films on Silicon Nitride

Tripathi, Shilini T.; Kotula, Paul G.; Singh, Manish K.; Ghosh, Chanchal G.; Bakan, Gokhan B.; Silva, Helena S.; Carter, Clive B.

Germanium antimony telluride has been the most used and studied phase-change material for electronic memory due to its suitable crystallization temperature, amorphous to crystalline resistance contrast, and stability of the amorphous phase. In this paper, the segregation of Ge in a Ge₂Sb₂Te₅ film of 30 nm thickness during heating inside the transmission electron microscope was observed and characterized. Furthermore, Ge₂Sb₂Te₅ film was deposited using sputtering on a Protochips Fusion holder and left uncapped in atmosphere for about four months. Oxygen incorporated within the film played a significant role in the chemical segregation observed which resulted in amorphous Ge-O island boundaries and Sb and Te rich crystalline domains. Such composition changes can occur when the phase-change material interfaces insulating oxide layers in an integrated device and can significantly impact its electrical and thermal properties.