Abstract
A Ta/TaOx/Pt stacked capacitor-like device for resistive switching was fabricated and examined. The tested device demonstrated stable resistive switching characteristics including uniform distribution of resistive switching operational parameters, highly promising endurance, and retention properties. To reveal the resistive switching mechanism of the device, micro structure analysis using high-resolution transmission electron microscope (HR-TEM) was performed. From the observation results, two different phases of Ta-metal clusters of cubic α-Ta and tetragonal β-Ta were founded in the amorphous TaOx mother-matrix after the device was switched from high resistance state (HRS) to low resistance state (LRS) by externally applied voltage bias. The observed Ta metal clusters unveiled the origin of the electric conduction paths in the TaOx thin film at the LRS.
Highlights
Resistive switching (RS) phenomena in various transition metal oxides (TMO) have been considerably investigated for next-generation non-volatile memory application as conventional sub-micron device fabrication skill confronts its physical limitation[1,2,3,4,5]
The device transits to the high resistance state (HRS) (Fig. 5(c)) through the RESET operation
Further microscopic analysis on the device at the HRS is missing in this paper, which can explicitly confirm the Ta metal phases may be partially left after the RESET
Summary
To figure out the crystalline structures, the electron DP shown in Fig. 4(d) was analysed and identified as Ta-metal phases and its equi-directional crystallographic planes. The lattice parameters extracted from each plane of the alpha-Ta have lattice strain less than 1% compared to the reference value It seems comprehensible when the crystalline Ta-metal phases are surrounded by the amorphous TaOx. the lattice mismatch can readily occur at the interfaces between the oxides and the metal phases. Those planes undisputedly appeared at integer times of the reciprocal vector of (321) as supposed, simultaneously satisfying the symmetry of (321) It reassured that the lattice parameters obtained from the electron DP of the tested device in the LRS agree with ones of the alpha-Ta phase.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
