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 TiO 2−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 TiO 2−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 TiO 2−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 °C of T S . The sample deposited at 200 °C had a significantly low 1/f noise parameter and a high universal bolometric parameter (β). However, at the substrate temperature of 250 °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 TiO 2−x films. As a result, the low resistivity of TiO 2−x sample deposited at 200 °C is a viable bolometric material for uncooled IR image sensors.