Evolution of resistive switching mechanism through H 2 O 2 sensing by using TaO x -based material in W/Al 2 O 3 /TaO x /TiN structure
Journal
Applied Surface Science
Journal Volume
433
Pages
51-59
Date Issued
2018
Author(s)
Chakrabarti, S.
Panja, R.
Roy, S.
Roy, A.
Samanta, S.
Dutta, M.
Ginnaram, S.
Maikap, S.
Cheng, H.-M.
Tsai, L.-N.
Chang, Y.-L.
Mahapatra, R.
Jana, D.
Qiu, J.-T.
Yang, J.-R.
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.
Type
journal article