Broadband antireflection coating for the near-infrared InAs/GaSb Type-Ⅱ superlattices photodetectors by lift-off process

摘要

Near-infrared InAs/GaSb Type-Ⅱ superlattices is widely used in biomimetics, sensing, color-imaging technology and other applications. An antireflection coating(AR coating) can help it perform better, making the infrared photodetector a higher responstivity and also a higher quantum efficiency. We produce a broadband AR coating by plasma-enhanced chemical vapor deposition(PECVD) then using the lift-off technology making no damage without any change in the usual Infrared detector process flow, a 260 nm SiO_2 AR coating is transform onto the surface of the infrared photodetector. After using the AR coating, the antireflection can provide up to 40% light gain, while the average reflectivity of the surface of InAs/GaSb type-Ⅱ superlattice is decreased from 33% to 14%. The responsitivity is increased obviously.