Abstract
Understanding of resistive switching mechanism through H 2 O 2 sensing and improvement of switching characteristics by using TaO x -based material in W/Al 2 O 3 /TaO x /TiN structure have been reported for the first time. Existence of amorphous Al 2 O 3 /TaO x layer in the RRAM devices has been confirmed by transmission electron microscopy. By analyzing the oxidation states of Ta 2+ /Ta 5+ for TaO x switching material and W 0 /W 6+ for WO x layer at the W/TaO x interface through X-ray photoelectron spectroscopy and H 2 O 2 sensing, the reduction-oxidation mechanism under Set/Reset occurs only in the TaO x layer for the W/Al 2 O 3 /TaO x /TiN structures. This leads to higher Schottky barrier height at the W/Al 2 O 3 interface (0.54 eV vs. 0.46 eV), higher resistance ratio, and long program/erase endurance of >10 8 cycles with 100 ns pulse width at a low operation current of 30 μA. Stable retention of more than 10 4 s at 85 °C is also obtained. Using conduction mechanism and reduction-oxidation reaction, current-voltage characteristic has been simulated. Both TaO x and WO x membranes have high pH sensitivity values of 47.65 mV/pH and 49.25 mV/pH, respectively. Those membranes can also sense H 2 O 2 with a low concentration of 1 nM in an electrolyte-insulator-semiconductor structure because of catalytic activity, while the Al 2 O 3 membrane does not show sensing. The TaO x material in W/Al 2 O 3 /TaO x /TiN structure does not show only a path towards high dense, small size memory application with understanding of switching mechanism but also can be used for H 2 O 2 sensors.
Original language | English |
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Pages (from-to) | 51-59 |
Number of pages | 9 |
Journal | Applied Surface Science |
Volume | 433 |
DOIs | |
Publication status | Published - Mar 1 2018 |
Externally published | Yes |
Keywords
- Al O layer
- H O sensing
- Simulation
- Switching mechanism
- TaO switching material
- WO membrane
ASJC Scopus subject areas
- General Chemistry
- Condensed Matter Physics
- General Physics and Astronomy
- Surfaces and Interfaces
- Surfaces, Coatings and Films