Fabrication of vanadium oxide thin film with high-temperature coefficient of resistance using V_2O_5/V/V_2O_5 multi-layers for uncooled microbolometers

摘要

Vanadium oxide thin film is a promising material for uncooled microbolometers due to its high temperature coefficient of resistance (TCR) at room temperature. It is, however, very difficult to deposit vanadium oxide thin films having a high temperature coefficient of resistance and low resistance because of the process limits in microbolometer fabrication. We present a novel fabrication method for vanadium oxide thin films having good electrical properties. Through the formation of a sandwich structure of V_2O_5 (100 A)/V (～80 A)/V_2O_5 (500 A) by a conventional sputter method and post-annealing at 300℃ in oxygen, a mixed phase of VO_x is formed. The results show that the mixed phase formed by this process has a high TCR of more than ―2%/℃ and low resistivity of < 0.1 Ω cm at room temperature.