Material relaxation in chalcogenide OTS SELECTOR materials

Nature of the mobility-gap states in amorphous Ge-rich Ge50Se50 was found to be related to homopolar Ge bonds in the chains/clusters of Ge atoms. Threshold switching material suffers GeGe bond concentration drift during material ageing, which can explain the observed reliability of the aGe50Se50 selector devices. Strong GeN bonds were introduced to alleviate the observed instability.