Selective growth and texturing of VO2(B) thin films for high-temperature microbolometers

Abstract

Vanadium oxides exhibit a broad spectrum of physical properties due to their ability to form various compounds and polymorphs. To utilise a particular property, it is essential to selectively synthesise a desired phase. Herein, we demonstrate a method to selectively and reproducibly grow (00l)-textured VO2(B) thin films using an amorphous SrTiO3 buffer layer by sputtering at <350 °C, which enables their direct integration with read-out-integrated-circuits (ROICs), glass, and polymer substrates. The VO2(B) films exhibit high temperature-coefficient-of-resistances (TCRs) (>−3.5%/K at 25 °C and >−1.5%/K at 95 °C) and low electrical resistivities (∼5 × 10−1 Ω cm at 25 °C and <1 × 10−1 Ω cm at 95 °C), which are favourable for realising highly-sensitive, low-noise, and high-temperature microbolometers. A robust thermal stability of these VO2(B) thin films at ambient pressure will provide new opportunities to incorporate thermal sensing functions to various electronics.