Effect of annealing on resistive switching properties of glancing angle deposition-assisted WO${}_3$ thin films

Herein, the impact of postdeposition annealing on resistive switching behavior of radio frequency magnetron sputtered WO${}_3$ thin films is reported. Films are deposited under glancing angle deposition (GLAD) configuration of sputtering at varying GLAD angle from 65° to 80°. Structure transition from monoclinic to orthorhombic phase in deposited WO${}_3$ films is perceived after ex situ annealing at temperature of 400 °C. Resistive switching properties show shift from bipolar to unipolar switching on postdeposition annealing. WO${}_3$ films show unipolar switching behavior after ex situ annealing for all prepared samples. The value of resistance in high resistance state is lowered after ex situ heating treatment and interestingly switching voltage also reduces to 3 V from 7 V after annealing treatment. The ratio of high to low resistance state for annealed WO${}_3$ film fabricated at 70° GLAD angle is achieved to be maximum (≈219). A detailed charge transport mechanism shows that ohmic behavior is dominant current conduction mechanism at lower applied voltage, while space charge limited current and Child's law are dominant at higher applied voltages. Obtained results encourage utilization of prepared WO${}_3$ thin films toward a wide variety of applications in optoelectronics, microelectronics, and environmental engineering along with advanced electronics such as resistive memory devices. (© 2023 Wiley‐VCH GmbH)