Extended Data Fig. 5: Different switching characteristics of SiTe_x film devices with three different stoichiometries on the 40 nm BEC.

Si-Te film-based devices with three different stoichiometries (95% Te (a), 75% Te (b), 50% Te (c)) are fabricated by co-sputtering Si and Te targets on the 40 nm BEC followed by sputtered W top electrode deposition to compare the electrical characteristics of various SiTe_x stoichiometries. Considering the bottom electrode contact area, the thickness of Si-Te films was selected as 35 nm to observe the clear transition between the selector and phase-change memory for various stoichiometries of Si-Te films⁴⁵. a. The 95% Te device, which has a higher Te atomic ratio compared to the SiTe₃, shows a threshold switching property with a large off-state resistance (a few tens of MΩ at 1 V), similar to chalcogenide-based selector devices. b. The 75% Te (SiTe₃) device shows reversible non-volatile phase-change memory behavior similar to the NFPCM. c. The 50% Te device, which has a lower Te atomic ratio compared to the SiTe₃, shows a threshold switching with a small on/off ratio and low off-state resistance (100 kΩ at 1 V). The results agree with the stoichiometry analysis from EDS analysis, where the SiTe_x filament is composed of 25% Si and 75% Te and exhibits non-volatile phase-change behaviors.