Rapid threshold switching dynamics of co-sputtered chalcogenide Ge₁₅Te₈₅ device for selector application

Abstract

Threshold switching is a unique characteristic feature in amorphous chalcogenide materials that establishes stable and fast switching between a high resistance OFF state and a conductive ON state in the amorphous phase, envisaging the electronic nature of two-terminal ovonic threshold switch (OTS) selectors in vertically stackable cross-point memory arrays. In this paper, we demonstrate voltage-dependent nanosecond threshold switching dynamics and stable OFF–ON transitions of co-sputtered thin Ge15Te85 film devices using ultrafast time-resolved current–voltage measurements. The time-resolved measurement of device current upon the application of voltage pulse reveals a stable threshold switching and OFF–ON transient characteristics of OTS devices and the measured delay time is found to decrease to few nanoseconds upon increasing the amplitude of the applied voltage pulse and such OTS characteristics are found to be stable even above 60% of the high value of threshold voltage. These experimental results found to be consistent with analytical solutions and also demonstrate a systematic trend in the voltage dependent switching properties enabling ultrafast threshold switching characteristics suitable towards designing reliable and stable OTS selector devices.

Ultrafast Threshold Switching Dynamics in Phase‐Change Materials

“…A large I on to I off ratio is desired for ideal OTS. Several materials such as Ge-Te-based alloys [20,63] and doped with elements such as Si, N, [14,20,[64][65][66] and Te doped with B-, C-, [67] and Ge-Se-based alloys [68] have been explored to develop the high-performance OTS devices. [69] Nevertheless, the search of a selector device with optimum performance is still on.…”

Threshold switching in chalcogenide GeTe and GeTeS thin films prepared via plasma enhanced atomic layer deposition

“…For example, the GeTe x thin film shows reliable TS if the value of x is 4, 5, or 6. 11,14,15 However, the as-deposited GeTe x thin film generally has a chemical composition of GeTe or GeTe 2 . [16][17][18] To address this issue, Lanxia et al proposed the super-cycle ALD method (Ge-Te and Te-Te) to increase the Te composition, but the TS behavior was not confirmed in GeTe x thin films.…”

“…For example, the GeTe x thin film shows reliable TS if the value of x is 4, 5, or 6. 11,14,15 However, the as-deposited GeTe x thin film generally has a chemical composition of GeTe or GeTe 2 . 16–18 To address this issue, Lanxia et al .…”