Fig. 4

a Resistance variation ratio versus baking time for different temperatures in TaO/AlO _x devices. The average initial resistance was 179 MOhm with a reading voltage of 2 V, and the LRS resistance degradation rate was calculated by the linear fitting method in log(R _ratio)–log(T) scale. b Estimated retention time (1000×) versus 1/kT plot. Each point contains data from 18 devices taken at a reading voltage of 2 V. The extracted activation energies were 0.38 eV in both the TaO/AlO _x and TaO/HfO _x devices. c Retention schematic diagram of different oxygen diffusion barriers in HfO _x or AlO _x with a TaO capping layer