Effect of Nitrogen Doping on Threshold Voltage in Amorphous Ga₂Te₃ for Application of Selector Devices

The implementation of ultrahigh-density cross-point array structures has received considerable interest as emerging storage devices, and threshold switching devices are regarded to be promising as to the suppression of leakage current in cross-point array structures. Threshold switching devices need to modulate the threshold voltage (V_th) depending on the various memory elements to achieve proper selector device in cross-point array structures. However, only limited methods are available for controlling V_th. Therefore, the nitrogen (N) doping effects on trap states, density of localized states, and V_th of the amorphous Ga₂Te₃ (a-Ga₂Te₃) selector devices are investigated herein. Furthermore, the electrical conduction behavior is fitted using a trap-controlled space charge limited conduction mechanism with two transition voltages, i.e., the space charge limited voltage (V_SCL) and trap-filled limited voltage (V_TFL). The optical bandgap energy and optical Urbach energy are affected by the N doping in a-Ga₂Te₃. In addition, N doping in a-Ga₂Te₃ increases the density of localized states. These effects increase both the transition voltages (V_SCL and V_TFL). Thus, doping a-Ga₂Te₃ with N reduces V_th when the trap states are changed. Furthermore, N-doped a-Ga₂Te₃ selector devices exhibit highly reliable switching up to 10⁹ cycles.