Development and integration of near atmospheric N2 ambient sputtered Au thin film for enhanced infrared absorption

The exceedingly fragile nature of thermally grown Au-black coating makes handling and patterning a critical issue. Infrared absorption characteristics of near atmospheric, N2 ambient DC sputtered Au thin films are studied for this purpose. The thin Au films are sputtered at different chamber pressures in Ar and N2/Ar gas ambient from 4.5 to 8.0 mbar and optimized for enhanced infrared absorption. The absorber film sputtered in N2/Ar ambient at 8.0 mbar chamber pressure offers significant absorption of medium to long wave infrared radiations. The micro-patterning of sputtered Au thin film is carried out by using conventional photolithography and metal lift off methods on a prefabricated µ-infrared detector array on Si (1 0 0) substrate. The steady state temperature response of sputtered film has been examined using nondestructive thermal imaging method under external heating of the detector array.