Electrical switching behavior of amorphous Ge15Te85 − xSix thin films with phase change memory applications

• Smooth and fast memory switching in a-Ge–Te–Si films.
• Composition dependence of switching fields of bulk and films are similar.
• Optical band gap studies support switching investigations.
• Observation of morphological changes in switched sample.

Amorphous Ge15Te85 − xSix thin film switching devices (1 ≤ x ≤ 6) have been deposited in sandwich geometry, on glass substrates with aluminum electrodes, by flash evaporation technique. These devices exhibit memory type electrical switching, like bulk Ge15Te85 − xSix glasses. However, unlike the bulk glasses, a-Ge15Te85 − xSix films exhibit a smooth electrical switching behavior. The electrical switching fields of a-Ge15Te85 − xSix thin film samples are also comparable with other chalcogenide samples used in memory applications.The switching fields of a-Ge15Te85 − xSix films have been found to increase with increasing Si concentration. Also, the optical band gap of a-Ge15Te85 − xSix films is found to increase with Si content. The observed results have been understood on the basis of increase in network connectivity and rigidity with Si addition.

Variation of threshold electric field with composition of amorphous thin films of Ge15Te85 − xSix samples (1 ≤ x ≤ 6), showing an increase due to network connectivity and rigidity as Si is incorporated into the Ge–Te system.Figure optionsDownload as PowerPoint slide