高制限Agドープによる原子スイッチデバイスのスイッチング特性の改善

Atomic switch (AS) devices are potential candidates as selector devices in cross-point array memory architecture. In this study, we improved the switching characteristics of an AS device by severely restricting Ag doping into the HfO2 electrolyte. Using a collimated sputtering process, we precisely controlled the amount of Ag doped in the electrolyte, which resulted in a higher threshold voltage (Vth) and enhanced turn-off speed compared with conventional AS devices. To understand the origin of these improvements, we analyzed both Ag-doped AS device and a conventional AS device with the framework of field-induced nucleation theory. Both devices showed an exponential relationship between delay time and voltage, but with different values of nucleation barrier energies (W0); the Ag-doped AS device exhibited a significantly higher W0. These results indicate that limit restricting Ag doping increases the nucleation barrier energy, leading to less stable filaments and thereby improving switching characteristics.