Substrate temperature dependent bolometric properties of TiO2-x films for infrared image sensor applications

Abstract

In this study, we investigated the substrate temperature (T-s) dependent bolometric properties on TiO2-x films for infrared image sensor applications. The film crystallinity was changed from amorphous to rutile phase with increasing the T-s. The decrement of resistivity with temperature in TiO2-x test-devices confirms the typical semiconducting property. All the test pattern devices have linear I-V characteristic performance which infers that the ohmic contact was well formed at the interface between the TiO2-x and the Ti electrode. The resistivity, activation energy (E-a) and the temperature coefficient of resistance (TCR) values of the device samples were decreased up to 200 degrees C of T-s. The sample deposited at 200 degrees C had a significantly low 1/f noise parameter and a high universal bolometric parameter (beta). However, at the substrate temperature of 250 degrees C, the E-a, TCR and the 1/f noise values were increased due to increase of the resistivity. The TCR and the 1/f noise values are proportional to the resistivity of TiO2-x films. As a result, the low resistivity of TiO2-x sample deposited at 200 degrees C is a viable bolometric material for uncooled IR image sensors. (C) 2016 Elsevier Ltd and Techna Group S.r.l. All rights reserved